Computer Networks

1. Case Study on
COMPUTER NETWORKS
SHIVAM BAJAJ

2. When You have Network , You have given Access of your Social Life to that Network .

3. Top Network Attacks
• Ransomware - Attackers manages to get a malicious file onto
your servers with the use form of phishing . Using phishing
keystroke logging files also managed .
• IOT - It is a growing field . no. of devices are increasing and
attack on that can cause chaos on enormous scale due to
unsecured digital devices or old protocols used .
• Social Engineering - It implies deceiving someone with
purpose of acquire sensitive information , like passwords ,
credit cards . Clone Phishing is used in this
• MIM Attacks - Session Hijacking . Spoofing .

4. • DOS - Denial of service attack , it is malicious attempt to
make a server or network resource unavailable to users ,
usually by suspending the services of hosts .
• DDOS - Distributed Denial of Service Attack
• SQL Injection - It is an SQL code injection technique ,
used to attack data driven app , in which malicious queries
are inserted into entry field for execution .

5. Typical Web Application Set Up

6. • SSL(Secure Sockets Layer ) is protocol for establishing
encrypted links b/w server and browser .
• It is the predecessor to TLS .
• When server return pages with https links , attacker
changes them to http and when browser uses links , MITM
intercepts and creates its own https con with server
• Result MITM sees all the packets in that network .
• Using nectar and OpenSSL , 2 line proxy can be created .
• listen on 80 port on host and redirect requests to port 443.
SSL Stripping

7. • URL Misinterpretation - Web servers fails to parse the
URL properly . eg - Unicode/ Superflous decode attack .
• Directory Browsing - ability to retrieve complete directory
listing within directories on web server . usually happens
when default document is missing .
• Reverse proxy server - proxy that typically sits behind the
firewall in private network and direct client to backend
server and provides an additional level of abstraction .
eg Compaq Insight manager .
• Java Decompilation - Java Byte code can be decompiled
quite effectively and disclose sensitive info like password.

8. • Source Code Disclosure - Ability to retrieve app files in
unparsed manner and can recover code . the code then
can be used to find further loopholes/trophies.
• Input Validation - Root cause of most web attacks .
Tampering with hidden fields , Bypassing client side
checking eg javascript .
• Butter Overflows - flaw that occurs when more data is
written to buffer , can cause DOS . Application Input Fields
eg - ColdFusion Dos .
• Fragrouter - network intrusion detection evasion toolkit . It
implements Insertion , Evasion and DOS attack .

9. Vulnerabilities in Layers of
OSI Model .

10. • Physical Layer - Physical destruction , obstruction ,
manipulation or malfunction of physical assets .
• Data Link layer - Mac flooding attack inmates switch with
data packets .
• Network Layer - ICMP flooding , attacker uses ICMP
messages to overload targeted network’s bandwidth .
• Transport Layer - SYN Flood , Smurf attack .
• Session Layer - attacker exploits a flaw in server software
running on switch,rendering telnet services unavailable .
• Presentation Layer - SSL stripping & Malformed SSL
requests , to tunnel HTTP attacks to the target server .
• Application Layer - DDos attack .Get requests , HTTP GET
HTTP Post , = website forms .