SKILL: Exploit Development

Metadata

• Skill Name: exploit-dev-curriculum
• Folder: offensive-exploit-dev-course
• Source: https://github.com/SnailSploit/offensive-checklist/blob/main/course.md

Description

Full exploit development course roadmap and syllabus: weekly topics, recommended reading, lab setup, and learning path from vulnerability classes through advanced exploitation. Use to structure exploit dev training or onboard new researchers.

Trigger Phrases

Use this skill when the conversation involves any of: exploit development course, exploit dev curriculum, learning path, syllabus, exploit dev training, vulnerability research training, course overview

Instructions for Claude

When this skill is active:

1. Load and apply the full methodology below as your operational checklist
2. Follow steps in order unless the user specifies otherwise
3. For each technique, consider applicability to the current target/context
4. Track which checklist items have been completed
5. Suggest next steps based on findings

Full Methodology

Exploit Development

Week 1: Foundations and Fuzzing Basics

Day 1: Introduction to Fuzzing

• Goal: Understand the fundamentals of fuzzing and get hands-on experience with AFL++.
• Activities:
  • Reading: "Fuzzing for Software Security Testing and Quality Assurance" by Ari Takanen(From 1.3.2 to 1.3.8 and 2.4.1 to 2.7.5.7).
  • Online Resource:
    • Fuzzing Book by Andreas Zeller - Read "Introduction" and "Fuzzing Basics."
    • AFL++ Documentation - Follow the quick start guide.
    • Interactive Module to Learn Fuzzing
  • Exercise:
    • Set up a Linux virtual machine (VM) with the necessary tools installed, including compilers and debuggers
    • Run AFL++ on a C program

# Setting up AFL++
sudo apt install build-essential gcc-13-plugin-dev cpio python3-dev libcapstone-dev pkg-config libglib2.0-dev libpixman-1-dev automake autoconf python3-pip ninja-build cmake
wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
sudo ./llvm.sh 19 all
curl --proto '=https' --tlsv1.2 -sSf "https://sh.rustup.rs" | sh
mkdir soft
cd soft
git clone --branch dev --depth 1 https://github.com/AFLplusplus/AFLplusplus
cd AFLplusplus
make distrib
sudo make install
# Phase 1
cd ~/ && mkdir tuts && cd tuts
git clone --branch main --depth 1 https://github.com/alex-maleno/Fuzzing-Module.git
cd Fuzzing-Module/exercise1 && mkdir build && cd build
CC=/usr/local/bin/afl-clang-fast CXX=/usr/local/bin/afl-clang-fast++ cmake ..
make && cd ../ && mkdir seeds && cd seeds && for i in {0..4}; do dd if=/dev/urandom of=seed_$i bs=64 count=10; done && cd ../build
afl-fuzz -i /home/dev/tuts/Fuzzing-Module/exercise1/seeds/ -o out -m none -d -- /home/dev/tuts/Fuzzing-Module/exercise1/build/simple_crash
# Phase 2
cd /home/dev/tuts/Fuzzing-Module/exercise2 && mkdir build && cd build
CC=/usr/local/bin/afl-clang-lto CXX=/usr/local/bin/afl-clang-lto++ cmake ..
make && cd ../ && mkdir seeds && cd seeds && for i in {0..4}; do dd if=/dev/urandom of=seed_$i bs=64 count=10; done && cd ../build
afl-fuzz -i /home/dev/tuts/Fuzzing-Module/exercise2/seeds/ -o out -m none -d -- /home/dev/tuts/Fuzzing-Module/exercise2/build/medium

Day 2: Continue Fuzzing with AFL++

• Goal: Understand and apply advanced fuzzing techniques.
• Activities:
  • Reading: Continue with "Fuzzing for Software Security Testing and Quality Assurance" (From 3.3 to 3.9.8).
  • Exercise:
    • Experiment with different AFL++ options (for example, dictionary-based fuzzing, persistent mode).
    • Running AFL++ with a real-world application like a file format parser to mimic real-world scenarios.

cd /home/dev/tuts && git clone --branch master --depth 1 https://github.com/davisking/dlib.git
cd dlib/tools/imglab && mkdir -p build && cd build && export AFL_USE_UBSAN=1 && export AFL_USE_ASAN=1
export ASAN_OPTIONS="detect_leaks=1:abort_on_error=1:allow_user_segv_handler=0:handle_abort=1:symbolize=0"
sudo apt install libx11-dev
cmake -DCMAKE_C_COMPILER=afl-clang-fast -DDLIB_NO_GUI_SUPPORT=0 -DCMAKE_CXX_COMPILER=afl-clang-fast++ -DCMAKE_CXX_FLAGS="-fsanitize=address,leak,undefined -g" -DCMAKE_C_FLAGS="-fsanitize=address,leak,undefined -g" ..
make -j8 && mkdir -p fuzz/image/in && cp /home/dev/tuts/dlib/examples/faces/testing.xml fuzz/image/in/
afl-fuzz -i fuzz/image/in -o fuzz/image/out -M Master -- ./imglab --stats @@
afl-fuzz -i fuzz/image/in -o fuzz/image/out -S Slave -- ./imglab --stats @@
sudo apt install gdb
git clone --branch master --depth 1 https://github.com/jfoote/exploitable.git ~/soft/exploitable
cd ~/soft/exploitable && sudo python3 setup.py install
wget -O ~/.gdbinit-gef.py -q https://gef.blah.cat/py && echo source ~/.gdbinit-gef.py >> ~/.gdbinit
sudo apt install valgrind
afl-collect -d crashes.db -e gdb_script -r -rr ./fuzz/image/out/Master ./afl-collect -j 8 -- ./imglab --stats @@%

Day 3: Introduction to Google FuzzTest

• Goal: Understand in-process fuzzing with FuzzTest.
• Activities:
  • Reading: Continue with "Fuzzing for Software Security Testing and Quality Assurance" (From 4.2.1 to 4.4).
  • Online Resource: Google FuzzTest - Follow the tutorial and examples.
  • Exercise: Write a simple fuzz target using FuzzTest.

cd /home/dev/tuts && mkdir first_fuzz_project && cd first_fuzz_project
git clone --branch main --depth 1 https://github.com/google/fuzztest.git
cat <<EOT >> CMakeLists.txt
cmake_minimum_required(VERSION 3.19)
project(first_fuzz_project)

# GoogleTest requires at least C++17
set(CMAKE_CXX_STANDARD 17)

add_subdirectory(fuzztest)

enable_testing()

include(GoogleTest)
fuzztest_setup_fuzzing_flags()
add_executable(
  first_fuzz_test
  first_fuzz_test.cc
)

link_fuzztest(first_fuzz_test)
gtest_discover_tests(first_fuzz_test)
EOT
cat <<EOT >> first_fuzz_test.cc
#include "fuzztest/fuzztest.h"
#include "gtest/gtest.h"

TEST(MyTestSuite, OnePlustTwoIsTwoPlusOne) {
  EXPECT_EQ(1 + 2, 2 + 1);
}

void IntegerAdditionCommutes(int a, int b) {
  EXPECT_EQ(a + b, b + a);
}
FUZZ_TEST(MyTestSuite, IntegerAdditionCommutes);
EOT
mkdir build && cd build
CC=clang-18 CXX=clang++-18 cmake -DCMAKE_BUILD_TYPE=RelWithDebug -DFUZZTEST_FUZZING_MODE=on ..
sudo apt install libssl-dev
cmake --build .
./first_fuzz_test --fuzz=MyTestSuite.IntegerAdditionCommutes

Day 4: Introduction to HonggFuzz

• Goal: Understand Fuzz methods, types, ...
• Activities:
  • Reading: Continue with "Fuzzing for Software Security Testing and Quality Assurance" (From 5.1.2 to 5.3.7).
  • Online Resource: HongFuzz
  • Exercise: Fuzz OpenSSL server and private key

cd /home/dev/soft && git clone --branch master --depth 1 https://github.com/google/honggfuzz.git
sudo apt-get install binutils-dev libunwind-dev libblocksruntime-dev clang
cd honggfuzz && make && sudo make install
cd /home/dev/tuts && git clone --branch master --depth=1 https://github.com/openssl/openssl.git
mv openssl openssl-master && cd openssl-master
CC=/usr/local/bin/hfuzz-clang CXX="$CC"++ ./config \
  -DPEDANTIC no-shared -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -O0 \
  -fno-sanitize=alignment -lm -ggdb -gdwarf-4 --debug -fno-omit-frame-pointer \
  enable-tls1_3 enable-weak-ssl-ciphers enable-rc5 enable-md2 \
  enable-ssl3 enable-ssl3-method enable-nextprotoneg enable-heartbeats \
  enable-aria enable-zlib enable-egd enable-msan
make -j$(nproc)
cat <<EOT >> make.sh
set -x
set -e
echo "Building honggfuzz fuzzers"
for x in x509 privkey client server; do
        hfuzz-clang -DBORINGSSL_UNSAFE_DETERMINISTIC_MODE -DBORINGSSL_UNSAFE_FUZZER_MODE -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -DBN_DEBUG -DLIBRESSL_HAS_TLS1_3 \\
        -O3 -g -DFuzzerInitialize=LLVMFuzzerInitialize -DFuzzerTestOneInput=LLVMFuzzerTestOneInput -I/home/dev/tuts/openssl-master/include \\
        -I/home/dev/soft/honggfuzz/examples/openssl -I/home/dev/soft/honggfuzz -g "/home/dev/soft/honggfuzz/examples/openssl/\$x.c" -o "libfuzzer.openssl-mastermemory.\$x" \\
        ./libssl.a ./libcrypto.a -lpthread -lz -ldl -fsanitize=\$1
done
EOT
bash make.sh memory
honggfuzz --input ~/soft/honggfuzz/examples/openssl/corpus_server/ -- ./libfuzzer.openssl-mastermemory.server
honggfuzz --input ~/soft/honggfuzz/examples/openssl/corpus_privkey/ -- ./libfuzzer.openssl-mastermemory.privkey

Day 5: Introduction to Syzkaller

• Goal: Begin kernel fuzzing with Syzkaller.
• Activities:
  • Tool: Install Syzkaller on a Linux VM.
  • Online Resource: Syzkaller Documentation
  • Exercise: Start fuzzing the Linux kernel with Syzkaller.

sudo apt update
sudo apt install make gcc flex bison libncurses-dev libelf-dev libssl-dev
cd ~/soft && git clone --branch v6.11 --depth 1 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git kernel
cd kernel && make defconfig && make kvm_guest.config
vim .config
# Edit these inside .config file
#CONFIG_KCOV=y
#CONFIG_DEBUG_INFO_DWARF4=y
#CONFIG_KASAN=y
#CONFIG_KASAN_INLINE=y
#CONFIG_CONFIGFS_FS=y
#CONFIG_SECURITYFS=y
#CONFIG_CMDLINE_BOOL=y
#CONFIG_CMDLINE="net.ifnames=0"
make olddefconfig && make -j`nproc`
sudo apt install debootstrap
mkdir ~/soft/image && cd ~/soft/image
wget https://raw.githubusercontent.com/google/syzkaller/master/tools/create-image.sh -O create-image.sh
chmod +x create-image.sh && ./create-image.sh --distribution trixie --feature full
sudo apt install qemu-system-x86
cd /tmp/ && sudo qemu-system-x86_64 \
	-m 2G -smp 2 -kernel ~/soft/kernel/arch/x86/boot/bzImage \
	-append "console=ttyS0 root=/dev/sda earlyprintk=serial net.ifnames=0" \
	-drive file=/home/dev/soft/image/trixie.img,format=raw \
	-net user,host=10.0.2.10,hostfwd=tcp:127.0.0.1:10021-:22 \
	-net nic,model=e1000 -enable-kvm -nographic \
	-pidfile vm.pid 2>&1 | tee vm.log
# ssh to QEMU instance in another terminal.
ssh -i ~/soft/image/trixie.id_rsa -p 10021 -o "StrictHostKeyChecking no" root@localhost
wget https://dl.google.com/go/go1.23.3.linux-amd64.tar.gz
tar -xf go1.23.3.linux-amd64.tar.gz && sudo mv go /usr/local
cd ~/soft/ && git clone --branch master --depth 1 https://github.com/google/syzkaller
cd syzkaller && export PATH=$PATH:/usr/local/go/bin && make
cat <<EOT >> my.cfg
{
	"target": "linux/amd64",
	"http": "127.0.0.1:56741",
	"workdir": "/home/dev/soft/syzkaller/workdir",
	"kernel_obj": "/home/dev/soft/kernel",
	"image": "/home/dev/soft/image/trixie.img",
	"sshkey": "/home/dev/soft/image/trixie.id_rsa",
	"syzkaller": "/home/dev/soft/syzkaller",
	"procs": 8,
	"type": "qemu",
	"vm": {
		"count": 4,
		"kernel": "/home/dev/soft/kernel/arch/x86/boot/bzImage",
		"cmdline": "net.ifnames=0",
		"cpu": 2,
		"mem": 2048
	}
}
EOT
mkdir workdir && sudo ./bin/syz-manager -config=/home/dev/soft/syzkaller/my.cfg
sudo apt install w3m w3m-img && w3m http://127.0.0.1:56741

Day 6: Analyzing Fuzzing Outputs

• Goal: Learn how to analyze and triage fuzzing outputs to identify unique crashes and potential vulnerabilities.
• Activities:
  • Reading:
    • Book: "Fuzzing for Software Security Testing and Quality Assurance" by Ari Takanen (Sections 6.1 to 6.5).
    • Article: Understanding Fuzzing and How It Discovers Security Flaws
  • Online Resources:
    • AddressSanitizer Documentation
    • GDB Python API
    • Exploitable Crash Analyzer
  • Exercise:
    • Set Up Crash Analysis Tools:
      • Install GDB and the exploitable plugin for crash classification.
      • Ensure AddressSanitizer is set up for detailed memory error reports.
    • Collect and Triage Crashes:
      • Use crashes from previous fuzzing sessions with AFL++, HonggFuzz, or Syzkaller.
      • Deduplicate crashes to focus on unique issues.
    • Analyze Crashes:
      • Use GDB and AddressSanitizer to investigate the root cause of each crash.
      • Classify the crashes based on severity and exploitability.
    • Automate Crash Analysis:
      • Write a script to automate the analysis of multiple crash files.
    • Deduplicate Crashes:
      • Use stack traces or tools like afl-collect to identify unique crashes.
    • Document Findings:
      • Create a report summarizing each unique crash, including:
        • The input that caused the crash.
        • The type of vulnerability (buffer overflow, null pointer de-reference,...).
        • Potential impact and severity.
    • Optional:
      • Explore other sanitizers like UndefinedBehaviorSanitizer (UBSan) for additional checks.
• Discussion Points:
  • The importance of accurately triaging crashes to prioritize security fixes.
  • Understanding false positives and how to filter them out.
  • The role of sanitizers in providing detailed diagnostics.
• Tips:
  • Always test crashes in a controlled environment to prevent unintended effects.
  • Keep your analysis tools up to date for the best results.
  • Collaborate with your team to verify findings and discuss mitigation strategies.
• Reflection:
  • How does effective crash analysis improve the overall security posture of software?
  • What challenges did you face during crash analysis, and how did you overcome them?

# Install required tools
sudo apt update
sudo apt install gdb python3-pip

# Install 'exploitable' GDB plugin
git clone https://github.com/jfoote/exploitable.git
cd exploitable
sudo python3 setup.py install

# Ensure AddressSanitizer is available (comes with Clang)
which clang
# If not installed, install Clang
sudo apt install clang

# Set up environment variables for AddressSanitizer
export ASAN_SYMBOLIZER_PATH=$(which llvm-symbolizer)
export ASAN_OPTIONS=symbolize=1:abort_on_error=1

# Compile a target program with AddressSanitizer
cd ~/tuts/ && git clone --branch master --depth 1 https://github.com/hardik05/Damn_Vulnerable_C_Program vuln
# change int main(char *argv,int argc) to int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
# use size instead of argc and data instead of argv
cd vuln && echo "IMG" > crash_input && clang -g -O1 -fsanitize=address,fuzzer -o target_asan dvcp.c

# Example: Analyze a crash using GDB and 'exploitable'
gdb -ex "run < crash_input" \
    -ex "exploitable" \
    -ex "quit" --args ./target_asan
# Script to automate crash analysis
mkdir analyzed_crashes
for crash in crash-*; do
    echo "Analyzing $crash"
    gdb -batch -ex "run < $crash" \
        -ex "exploitable" \
        --args ./target_asan &> analyzed_crashes/$(basename $crash).log
done

curl --proto '=https' --tlsv1.2 -sSf "https://sh.rustup.rs" | sh
cargo install casr
casr-san -o asan.casrep -- ./test_asan_df

# Install afl-collect if using AFL++
sudo apt install afl-utils

# Collect and deduplicate crashes
afl-collect -rr --crashdir crashes_deduped \
            --workdir afl_output -j 4 \
            -- ./target_asan @@
# Compile with UBSan
clang -g -O1 -fsanitize=undefined -o target_ubsan target.c

Day 7: Review and Recap

• Goal: Consolidate the knowledge gained during Week 1 by reviewing key concepts, clarifying doubts, and reinforcing practical skills in fuzzing and, initial crash analysis.
• Activities:
  • Review Session:
    • Revisit the key concepts from Days 1 to 6:
      • Fundamentals of fuzzing and its importance in security testing.
      • Hands-on experience with fuzzing tools: AFL++, FuzzTest, HonggFuzz, and Syzkaller.
      • Setting up fuzzing environments and running basic to advanced fuzzing campaigns.
      • Initial crash analysis and triaging techniques.
    • Discuss any challenges faced during the exercises and share solutions.
  • Reading:
    • Summary Articles:
      • A Brief History of Fuzzing
      • Best Practices in Fuzzing
    • Documentation:
      • Revisit the documentation for the tools used to reinforce understanding of their features and options.
  • Knowledge Check:
    • Quiz:
      • Prepare a set of questions to test your understanding of the week's material.
        • What are the main differences between AFL++ and HonggFuzz?
        • How does in-process fuzzing with FuzzTest differ from traditional fuzzing methods?
        • Explain the purpose of sanitizers like AddressSanitizer in fuzzing campaigns.
        • Describe the process of setting up Syzkaller for kernel fuzzing.
    • Flashcards:
      • Create flashcards for important terms and concepts, such as:
        • Mutation-based fuzzing
        • Coverage-guided fuzzing
        • Sanitizers
        • Crash triaging
        • Deduplication of crashes
  • Hands-On Practice:
    • Consolidate Exercises:
      • Re-run previous fuzzing sessions with additional configurations to reinforce learning.
      • Try fuzzing a new simple application using the tools you've learned.
    • Collaborative Learning:
      • If possible, discuss with peers or online communities about your findings and methodologies.
      • Share your crash analysis reports and get feedback.
  • Deep Dive into Topics of Interest:
    • Choose a topic or tool from the week that you found most challenging or interesting and spend extra time exploring it.
      • For example, delve deeper into Syzkaller's syscall descriptions or explore advanced options in AFL++.
• Discussion Points:
  • Challenges and Solutions:
    • Reflect on any obstacles you faced during the exercises.
    • Discuss strategies for overcoming common issues in fuzzing campaigns, such as dealing with large numbers of crashes or configuring complex tools.
  • Real-World Applications:
    • Consider how the fuzzing techniques learned can be applied to real-world software projects.
    • Discuss the impact of effective fuzzing on software security and quality assurance.
• Tips:
  • Documentation and Note-Taking:
    • Maintain detailed notes of your configurations, commands used, and observations from your fuzzing sessions.
    • Document any anomalies or unexpected behavior for future reference.
  • Tool Mastery:
    • Familiarize yourself with the command-line options and configurations of each tool.
    • Practice writing custom scripts to automate repetitive tasks in your fuzzing workflow.
• Reflection:
  • Self-Assessment:
    • Evaluate your understanding of the week's material.
    • Identify areas where you feel confident and areas that may require additional study.
  • Goal Setting:
    • Set specific objectives for the next week based on your reflection.
    • For example, aim to understand advanced features of a particular fuzzing tool or improve your crash analysis skills.
• Optional Activity:
  • Beginner's Capture the Flag (CTF):
    • Participate in a beginner-level CTF that focuses on binary exploitation and fuzzing challenges.
    • Apply the skills you've learned in a competitive and practical environment.
• Additional Resources:
  • Books:
    • "The Art of Software Security Assessment" by Mark Dowd, John McDonald, and Justin Schuh – Chapters on fuzzing and vulnerability discovery.
  • Online Courses:
    • Coursera: Software Security – Sections related to input validation and fuzz testing.
• Action Items for Next Week:
  • Prepare for Week 2, which focuses on Crash Analysis.
  • Ensure your environment is set up with debugging tools like GDB, WinDbg (for Windows), and other necessary utilities.

Week 2: Crash Analysis