Menu

Individual skill

exploiting-format-string-vulnerabilities

0upvotes

Methodology for exploiting format string bugs where attacker-controlled data reaches the format argument of printf-family functions, enabling stack/memory disclosure (info leaks for ASLR/PIE/canary defeat) and arbitrary write primitives (%n) to hijack control flow via GOT/.fini_array overwrites.

internal/tools/skills/data/binary-exploitation/exploiting-format-string-vulnerabilities/SKILL.md

Read pinned source

Source commit d42f381ad34843e71a42658e5c57290c713e85af

What was checked

Matches the observed repository HEAD
Yes
Scanner rules are current
Yes
Repository scan complete
No
Skill scan complete
No
Observed behavior
Instructions only
Last checked
Nov 9, 2026

These are observations at the recorded commit, not a guarantee of safety. Review the source before running it.

Install this skill

Choose an agent in your Stack or copy a command below. Commands fetch the pinned commit and copy only this skill directory. Existing destinations are refused. Copying a command does not install anything.

An install command is unavailable: current rules, complete repository and skill scans, an eligible behavior level and a permitted license are required.

Repository context

Repository stars (not skill ratings)
1,329
Repository last updated
Nov 9, 2026
License
Apache-2.0

Observed agent integration: No specific integration evidence. Standard SKILL.md installation does not imply verified compatibility.

Files and excerpt

File metadata and permitted, redacted excerpts come from the recorded scan. Source links are pinned to that commit.

Browse files
Read excerpt

# Exploiting Format String Vulnerabilities

## When to Use

- During authorized binary/exploitation assessments when attacker input is passed as the **first argument** (the format)
  to `printf`, `fprintf`, `sprintf`, `snprintf`, `vprintf`, `syslog`, or similar.
- When you need a memory-disclosure primitive to leak stack contents, a libc/PIE pointer, or a stack canary to defeat
  ASLR/PIE/canary protections.
- When you have an arbitrary-write primitive opportunity via `%n`/`%hn` to overwrite a GOT entry, `.fini_array`, a saved
  return address, or a function pointer.
- On Windows x64 services where a buggy `_snprintf(dst, len, attacker_fmt)` call provides no varargs and conversions read
  pointers out of RCX/RDX/R8/R9 registers.

## Critical: Concepts/Steps Most Often Missed
Back to top