4 Task 2: Understanding the Vulnerable Program The vulnerable program used in this lab is
called stack. c, which is in the code folder. This program has a buffer-overflow vulnerability, and
your job is to exploit this vulnerability and gain the root privilege. The code listed below has
some non-essential information removed, so it is slightly different from what you get from the
lab setup file. Listing 2: The vulnerable program (stack. c) The above program has a buffer
overflow vulnerability. It first reads an input from a file called badf ile, and then passes this input
to another buffer in the function bof () . The original input can have a maximum length of 517
bytes, but the buffer in bof () is only BUF_SIZE bytes long, which is less than 517. Because
strcpy () does not check boundaries, buffer overflow will occur. Since this program is a root-
owned Set-UID program, if a normal user can exploit this buffer overflow vulnerability, the user
might be able to get a root shell. It should be noted that the program gets its input from a file
called badfile. This file is under users' control. Now, our objective is to create the contents for
badfile, such that when the vulnerable program copies the contents into its buffer, a root shell can
be spawned. Compilation. To compile the above vulnerable program, do not forget to turn off the
StackGuard and the non-executable stack protections using the -fno-stack-protector and "-z
execstack " options. After the compilation, we need to make the program a root-owned Set-UID
program. We can achieve this by first change the ownership of the program to root (Line (1), and
then change the permission to 4755 to enable the Set-UID bit (Line (2)). It should be noted that
changing ownership must be done before turning on the Set-UID bit, because ownership change
will cause the Set-UID bit to be turned off. The compilation and setup commands are already
included in Makefile, so we just need to type make to execute those commands. The variables
L1, ..., L4 are set in Makefile; they will be used during the compilation. We have chosen a
different set of values for these variables, you need to change them in Makefile. The values are
listed below: - L1: 100 - L2: 150 - L3: 200 - L4: 10 5 Task 3: Launching Attack on 32-bit
Program (Level 1) 5.1 Investigation To exploit the buffer-overflow vulnerability in the target
program, the most important thing to know is the distance between the buffer's starting position
and the place where the return-address is stored. We will use a debugging method to find it out.
Since we have the source code of the target program, we can compile it with the debugging flag
turned on. That will make it more convenient to debug. We will add the g flag to gcc command,
so debugging information is added to the binary. If you run make, the debugging version is
already created. We will use gdb to debug stack-L1-dbg. We need to create a file called badfile
before running the program. Note 1. When gdb .
When Good Code Goes Bad: Tools and Techniques for Troubleshooting PloneDavid Glick
Using real issues encountered in the wild, this session will help beginning integrators gain confidence in knowing what to do when Plone fails to behave as expected. Learn how to solve common problems like "My changes aren't taking effect" and "My Zope instance won't start," as well as how to use pdb to investigate more complex Python errors.
This talk is targeted at integrators who have some experience with Plone, but who are not confident in troubleshooting errors and other unexpected behavior. Knowledge of Python is not required, though at least a cursory familiarity with some programming language will make the talk more digestible.
When Good Code Goes Bad: Tools and Techniques for Troubleshooting PloneDavid Glick
Using real issues encountered in the wild, this session will help beginning integrators gain confidence in knowing what to do when Plone fails to behave as expected. Learn how to solve common problems like "My changes aren't taking effect" and "My Zope instance won't start," as well as how to use pdb to investigate more complex Python errors.
This talk is targeted at integrators who have some experience with Plone, but who are not confident in troubleshooting errors and other unexpected behavior. Knowledge of Python is not required, though at least a cursory familiarity with some programming language will make the talk more digestible.
.NET Conf 2019 Tel-Aviv Israel
There are cases where bugs are discovered only after the product is shipped and used by the end-users. The main reason for these bugs that appear only in the production environment is the use of real user scenarios with real user data. Production debugging is about solving customer-facing issues that aren't easily reproducible in the development or testing environments. When it comes to a cloud-hosted application, production debugging becomes even harder. The code is running on multiple hosts, a business flow can span many services. A remote debugging session with the cloud is dangerous and may introduce side effects to the currently running software, such as performance degradation, interruption of service, and data correctness issues.
In this lecture, we will see how we can remote debug our cloud staging environment, and how we can use Visual Studio Snapshot debugger to set Snapshots and Log points in our production environment.
To get even more insights, the audience will see a revolutionary tool and approach for a collaborative production debugging – OzCode Debugging as a Service (DaaS), where the DevOps and the Dev team can solve production problems together!
You will learn:
1. The difficulties of debugging a modern cloud-hosted application
2. Methods and tools for capturing the state and debugging cloud-hosted services
IDA Vulnerabilities and Bug Bounty by Masaaki ChidaCODE BLUE
IDA Pro is an advanced disassembler software and often used in vulnerability research and malware analysis. IDA Pro is used to analyse software behavior in detail, if there was a vulnerability and the user is attacked not only can it have impact in a social sense but also impact legal proceedings. In this presentation I will discuss the vulnerabilities found and attacks leveraging the vulnerabilities and Hex-rays's remediation process and dialogue I had with them.
http://codeblue.jp/en-speaker.html#MasaakiChida
GDB - a tough nut to crack: only a few bugs found by PVS-StudioPVS-Studio
GDB is a tool that is hard to live without. Of course, as Brooks says: "The quality in software development is achieved through proper design, not by endless testing". However, proper design doesn't protect from logical errors, typos, null pointers, and so on. That's why various debugging tools, like GDB, come to help. My aim is to show that static code analyzers are also very useful tools which help to detect errors at the early stages of development. It's much better if the bug is fixed in the code before the testing and debugging stage. To demonstrate the benefits of static code analysis, let's delve inside GDB and look for errors, using PVS-Studio.
4- -2 pts- Consider the ER schema for the MOVIES database as tollows-.pdfatozshoppe
4. [2 pts] Consider the ER schema for the MOVIES database as tollows: Assume that MOVES is
a populated database. ACTOR is used as a generic term and indudes actresses. Given the
constraints shown in the ER schema, respond to the following statements with True, False, or
Maybe. Assign a response of Maybe to statements that, although not explictly shown to be True,
carnot be proven False based on the schema as shown Justily each answer a) There are some
actors who have acted in more than ten movies: b) Some actors have done a lead role in multele
movies. c) A mevie can have a mininum of two lead actors. d) Every director has been an actor
in some movie:.
.NET Conf 2019 Tel-Aviv Israel
There are cases where bugs are discovered only after the product is shipped and used by the end-users. The main reason for these bugs that appear only in the production environment is the use of real user scenarios with real user data. Production debugging is about solving customer-facing issues that aren't easily reproducible in the development or testing environments. When it comes to a cloud-hosted application, production debugging becomes even harder. The code is running on multiple hosts, a business flow can span many services. A remote debugging session with the cloud is dangerous and may introduce side effects to the currently running software, such as performance degradation, interruption of service, and data correctness issues.
In this lecture, we will see how we can remote debug our cloud staging environment, and how we can use Visual Studio Snapshot debugger to set Snapshots and Log points in our production environment.
To get even more insights, the audience will see a revolutionary tool and approach for a collaborative production debugging – OzCode Debugging as a Service (DaaS), where the DevOps and the Dev team can solve production problems together!
You will learn:
1. The difficulties of debugging a modern cloud-hosted application
2. Methods and tools for capturing the state and debugging cloud-hosted services
IDA Vulnerabilities and Bug Bounty by Masaaki ChidaCODE BLUE
IDA Pro is an advanced disassembler software and often used in vulnerability research and malware analysis. IDA Pro is used to analyse software behavior in detail, if there was a vulnerability and the user is attacked not only can it have impact in a social sense but also impact legal proceedings. In this presentation I will discuss the vulnerabilities found and attacks leveraging the vulnerabilities and Hex-rays's remediation process and dialogue I had with them.
http://codeblue.jp/en-speaker.html#MasaakiChida
GDB - a tough nut to crack: only a few bugs found by PVS-StudioPVS-Studio
GDB is a tool that is hard to live without. Of course, as Brooks says: "The quality in software development is achieved through proper design, not by endless testing". However, proper design doesn't protect from logical errors, typos, null pointers, and so on. That's why various debugging tools, like GDB, come to help. My aim is to show that static code analyzers are also very useful tools which help to detect errors at the early stages of development. It's much better if the bug is fixed in the code before the testing and debugging stage. To demonstrate the benefits of static code analysis, let's delve inside GDB and look for errors, using PVS-Studio.
Similar to 4 Task 2- Understanding the Vulnerable Program The vulnerable program.pdf (20)
4- -2 pts- Consider the ER schema for the MOVIES database as tollows-.pdfatozshoppe
4. [2 pts] Consider the ER schema for the MOVIES database as tollows: Assume that MOVES is
a populated database. ACTOR is used as a generic term and indudes actresses. Given the
constraints shown in the ER schema, respond to the following statements with True, False, or
Maybe. Assign a response of Maybe to statements that, although not explictly shown to be True,
carnot be proven False based on the schema as shown Justily each answer a) There are some
actors who have acted in more than ten movies: b) Some actors have done a lead role in multele
movies. c) A mevie can have a mininum of two lead actors. d) Every director has been an actor
in some movie:.
4- A man named Paul has type A blood- His father is type AB and his mo.pdfatozshoppe
4. A man named Paul has type A blood. His father is type A B and his mother is homozygous for
type A . He married Sandra who also has type A blood but whose father is type A and whose
mother is type B. What is the probability that their first child will have type A blood? What is the
probability that their second child will have type O blood?.
4- A density-dependent population grows according to dNt-dt-0-4Nt0-002.pdfatozshoppe
4. A density-dependent population grows according to dNt / dt = 0.4 Nt 0.002 ( Nt ) 2 , where Nt
is the population size at continuous time t . A. Find the carrying capacity of the population, Show
your work..
4- (8 points) The figure below shows the double Holliday junction mode.pdfatozshoppe
4. (8 points) The figure below shows the double Holliday junction model of recombination. How
can this structure be resolved to give rise to recombinant chromatids? On the figure below,
indicate one possible way the DNA strands could be cut and re-ligated, leading to recombinant
chromosomes. Draw the resulting recombinant chromatids below..
34- The Neurospora octad shown came from a cross between m+and mstrain.pdfatozshoppe
34. The Neurospora octad shown came from a cross between m + and m strains. a. Is this an MI
or an MII octad or neither? Explain. b. Diagram the production of this octad. c. Is it possible to
observe evidence of heteroduplex formation in a Neurospora ascus even if gene conversion did
not occur during formation of the octad? Explain..
4- (10 points) Solve the following recurrence relation using tree meth.pdfatozshoppe
4. (10 points) Solve the following recurrence relation using tree method and obtain the big O
complexity of T ( n ) . Show all the steps in your answer including a tree diagram. T ( n ) = 2 T (
n /2 ) + n.
33-34 will upvote Which of the following statements is correct- When a.pdfatozshoppe
33/34
will upvote
Which of the following statements is correct? When a firm's accounts payable balance increases
and, because it is a liability, that represents a source of funds on the statement of cash flows. The
common size balance sheet outlines the sources of the firm's cash inflows and shows where the
cash outflows went. Liabilities are the tangible or intangible things that a firm owns. Earnings
Before Taxes ( EBT ) = Net Income - Operating Expenses. All the answers are correct. Which of
the following statements is correct? Cash flow is the number one concern for financial analysts.
All the answers are correct. Retained earnings is the accumulation of the distributed profits of the
firm as dividends. Earnings Before Interest and Taxes ( EBIT ) = EBT - Interet Expense.
Common-size statements make it difficult to see trends over time..
4) A firm with unlimited funds must evaluate five projects- Projects 1.pdfatozshoppe
4) A firm with unlimited funds must evaluate five projects. Projects 1 and 2 are independent and
Projects 3, 4, and 5 are mutually exclusive. The projects are listed with their returns. Determine
and discuss the ranking of the projects on the basis of their returns from the best to the worst
according to their acceptability to the firm..
31- of all college students major in STEM (Science- Technology- Engine.pdfatozshoppe
31% of all college students major in STEM (Science, Technology, Engineering, and Math). If 43
college students are randomly selected, find the probability that
a. Exactly 14 of them major in STEM.?
b. At most 13 of them major in STEM. ?
c. At least 13 of them major in STEM. ?
d. Between 11 and 16 (including 11 and 16) of them major in STEM.?.
37- D Genetic and genomic research can have D) 1 social and environm.pdfatozshoppe
37. D Genetic and genomic research can have D) 1 social and environmental implications.
Imagine that you are a journalist writing an article for the magazine Ethics in a Changing World.
You have been asked to research and explain the social and environmental implications of
current research related to genetics. Suggested topics include stem cell research for regenerative
medicine, transgenic crops to reduce hunger, genetic screening for specific diseases, and
reproductive cloning..
36- The project management triangle is a simple communication model-.pdfatozshoppe
36. The project management triangle is a simple communication model. What goes in the middle
of the triangle?
a. Cost
b. Schedule
c. Quality
d. Objectives
37. Projects may have problems because of team members that are selected to work on the
project. In other words, people are needed to make projects work, and sometimes certain people
are better suited for individual work than project work.
Group of answer choices
True
False
38. The Work Breakdown Structure (WBS) is a random listing of what must be done during a
project.
True
False
39.The lowest level of the Work Breakdown Structure is time, in weekly buckets.
True
False
40. A __________ Diagram is a model used to visually show project activities and their
sequential relationships by use of nodes and arrows.
a. Project
b. Triangle
c. Network
d. System
.
33- Helper T cells are differentiated into Th1 and Th2 according to a-.pdfatozshoppe
33. Helper T cells are differentiated into Th1 and Th2 according to a. the antigen they are
exposed to b. site of maturation c. presence of CD 3 d. secreted cytokines e. the type of cells they
kill 38. Which cell type interacts with both the humoral and cell mediated immune pathways: a.
plasma cells b. cytotoxic T cells c. natural killer cells d. CD3 cells e. helper T cells.
34-Explain differences between Lytic cycle and Lysogenic cycle- 35-.pdfatozshoppe
34.Explain differences between Lytic cycle and Lysogenic cycle.
35.What are the bacterial defense mechanisms against bacteriophage infection?
36.Expression of Lac operon in E. coli is controlled by the presence or absence of glucose and
lactose in the growth medium. Complete the following table.
32- Which of these climographs shows an equatorial location- 33- Upwel.pdfatozshoppe
32. Which of these climographs shows an equatorial location? 33. Upwelling of deep ocean
water off Peru occurs during an El Nino year. 34. Which is not part of Milankovitch Cycles? 35.
A large fraction of climate scientists oppose the theory that Earth's atmosphere is warming and
that humans are playing a significant role in that warming. 36. It has been well understood for
more than a century that carbon dioxide levels in the atmosphere influence global air
temperatures. 37. A Type 1 error is to a hypothesis that is correct, and a Type 2 error is to an
error that is wrong. 38. Which of these variables would be the dependent variable in a study
designed to determine the effects of light on the growth rate for a particular type of plant species
grown in lab? 39. What is a simulation that uses mathematical equations to represent the
phenomena under study? 40. In a study on a new drug, Group A is given the drug and Group B is
given the placebo. In this study, which is the control group?.
31- Saving Account Write a menu-driven program that allows the user to.pdfatozshoppe
31. Saving Account Write a menu-driven program that allows the user to make transactions to a
savings account. Assume that the account initially has a balance of $1 , 000 . See Fig. 3.43..
3- What would be the most likely result if the domain of pRB that lets.pdfatozshoppe
3. What would be the most likely result if the domain of pRB that lets it bind to E2F was
mutated/defective?
a) Increased likelihood of entry into S phase.
b) Decreased likelihood of entry into S phase.
c) Increased pRB phosphorylation.
d) Decreased pRB phosphorylation.
e) None of these..
3- What is the most dangerous greenhouse gas that has been released in.pdfatozshoppe
3. What is the most dangerous greenhouse gas that has been released in association with shifts in
volcanic activity, leading to rapid and severe global warming? a) Oxygen b) Carbon dioxide c)
Methane d) Water vapor 4. From the perspective of the causes of extinction, a reduction in the
population of a species is... a) A biological factor b) An environmental change c) A discrete
event d) None of the above 5. What is one reason that times of climatic warming are often
associated with decreased oxygenation of the seafloor? a) Climatic warming is always associated
with asteroid impacts, which results in obliteration of the asteroid into fine particles that absorb
oxygen in the ocean b) Because warm water can hold less dissolved oxygen than cool water c)
All times of rapid climatic warming are associated with a total loss of photosynthetic organisms
d) None of the above 6. What is a major hazard associated with development of LIPs? a) Release
of large amounts of SO 2 into the atmosphere, leading to widespread sulfuric acid rain b) Release
of large amounts of CO 2 into the atmosphere, leading to climatic warming c) Release of large
amounts of fine solid material (ash, dust, etc.) which can block out the sun and destabilize the
food web d) All of the above are hazards associated with LIP development 7. Is there a universal
cause for mass extinction events on our planet? a) Yes-rapid climatic cooling b) Yes - drops in
oxygen levels in the ocean c) Yes asteroid impacts d) All of these have been proposed as
universal causes of extinctions at some point, but their significance and roles, if any, vary from
event to event.
3- Your random sample was obtained from the population of participants.pdfatozshoppe
3. Your random sample was obtained from the population of participants for your chosen data
set. Based on the histogram from your random sample, how would you describe the population
of participants for your chosen IAT data set? Do you think the population is similar to the U.S.
population?
Frequency Frequency.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
4 Task 2- Understanding the Vulnerable Program The vulnerable program.pdf
1. 4 Task 2: Understanding the Vulnerable Program The vulnerable program used in this lab is
called stack. c, which is in the code folder. This program has a buffer-overflow vulnerability, and
your job is to exploit this vulnerability and gain the root privilege. The code listed below has
some non-essential information removed, so it is slightly different from what you get from the
lab setup file. Listing 2: The vulnerable program (stack. c) The above program has a buffer
overflow vulnerability. It first reads an input from a file called badf ile, and then passes this input
to another buffer in the function bof () . The original input can have a maximum length of 517
bytes, but the buffer in bof () is only BUF_SIZE bytes long, which is less than 517. Because
strcpy () does not check boundaries, buffer overflow will occur. Since this program is a root-
owned Set-UID program, if a normal user can exploit this buffer overflow vulnerability, the user
might be able to get a root shell. It should be noted that the program gets its input from a file
called badfile. This file is under users' control. Now, our objective is to create the contents for
badfile, such that when the vulnerable program copies the contents into its buffer, a root shell can
be spawned. Compilation. To compile the above vulnerable program, do not forget to turn off the
StackGuard and the non-executable stack protections using the -fno-stack-protector and "-z
execstack " options. After the compilation, we need to make the program a root-owned Set-UID
program. We can achieve this by first change the ownership of the program to root (Line (1), and
then change the permission to 4755 to enable the Set-UID bit (Line (2)). It should be noted that
changing ownership must be done before turning on the Set-UID bit, because ownership change
will cause the Set-UID bit to be turned off. The compilation and setup commands are already
included in Makefile, so we just need to type make to execute those commands. The variables
L1, ..., L4 are set in Makefile; they will be used during the compilation. We have chosen a
different set of values for these variables, you need to change them in Makefile. The values are
listed below: - L1: 100 - L2: 150 - L3: 200 - L4: 10 5 Task 3: Launching Attack on 32-bit
Program (Level 1) 5.1 Investigation To exploit the buffer-overflow vulnerability in the target
program, the most important thing to know is the distance between the buffer's starting position
and the place where the return-address is stored. We will use a debugging method to find it out.
Since we have the source code of the target program, we can compile it with the debugging flag
turned on. That will make it more convenient to debug. We will add the g flag to gcc command,
so debugging information is added to the binary. If you run make, the debugging version is
already created. We will use gdb to debug stack-L1-dbg. We need to create a file called badfile
before running the program. Note 1. When gdb stops inside the bof () function, it stops before the
ebp register is set to point to the current stack frame, so if we print out the value of ebp here, we
will get the caller's ebp value. We need to use next to execute a few instructions and stop after
the ebp register is modified to point to the stack frame of the bof () function. The SEED book is
based on Ubuntu 16.04, and gdb's behavior is slightly different, so the book does not have the
next step. Note 2. It should be noted that the frame pointer value obtained from g db is different
from that during the actual execution (without using gdb). This is because gdb has pushed some
environment data into the stack before running the debugged program. When the program runs
directly without using gdb, the stack does not have those data, so the actual frame pointer value
will be larger. You should keep this in mind when constructing your payload. 5.2 Launching
Attacks To exploit the buffer-overflow vulnerability in the target program, we need to prepare a
payload, and save it inside badfile. We will use a Python program to do that. We provide a
skeleton program called exploit.py, which is included in the lab setup file. The code is
incomplete, and students need to replace some of the essential values in the code. Listing 3:
exploit.py In your lab report, in addition to providing screenshots to demonstrate your
2. investigation and attack, you also need to explain how the values used in your exploit.py are
decided. These values are the most important part of the attack, so a detailed explanation can
help the instructor grade your report. Only demonstrating a successful attack without explaining
why the attack works will not receive many points. 6 Task 4: Launching Attack without
Knowing Buffer Size (Level 2) In the Level-1 attack, using gdb, we get to know the size of the
buffer. In the real world, this piece of information may be hard to get. For example, if the target
is a server program running on a remote machine, we will not be able to get a copy of the binary
or source code. In this task, we are going to add a constraint: you can still use g db , but you are
not allowed to derive the buffer size from your investigation. Actually, the buffer size is
provided in Makefile, but you are not allowed to use that information in your attack. Your task is
to get the vulnerable program to run your shellcode under this constraint. We assume that you do
know the range of the buffer size, which is from 100 to 200 bytes. Another fact that may be
useful to you is that, due to the memory alignment, the value stored in the frame pointer is
always multiple of four (for 32-bit programs). Please be noted, you are only allowed to construct
one payload that works for any buffer size within this range. You will not get all the credits if
you use the brute-force method, i.e., trying one buffer size each time. The more you try, the
easier it will be detected and defeated by the victim. That's why minimizing the number of trials
is important for attacks. In your lab report, you need to describe your method, and provide
evidences.