Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add SecurityTalent/bugskill-ai --skill arbitrary-write-to-rcegit clone --depth 1 https://github.com/SecurityTalent/bugskill-aiWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/securitytalent/bugskill-ai/arbitrary-write-to-rce)<a href="https://agentmods.dev/skills/securitytalent/bugskill-ai/arbitrary-write-to-rce"><img src="https://agentmods.dev/badge/skills/securitytalent/bugskill-ai/arbitrary-write-to-rce/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/securitytalent/bugskill-ai/arbitrary-write-to-rce"><img src="https://agentmods.dev/badge/skills/securitytalent/bugskill-ai/arbitrary-write-to-rce.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00080 | $0.03783 |
| Opus 5.5 | $0.00032 | $0.01513 |
| Sonnet 5.5 | $0.00016 | $0.00757 |
| Haiku 4.5 | $0.00008 | $0.00378 |
Grade B, and why
arbitrary-write-to-rce scanned grade B with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Unrestricted tool accessmediumExcessive agency
A wildcard tool grant or "run any command" leaves no least-privilege boundary at all.
**Overwrite the kernel's `modprobe_path` to execute arbitrary commands as root.** This is a copy
100% identical to arbitrary-write-to-rce — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 362 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SKILL: Arbitrary Write to Code Execution — Expert Attack Playbook
AI LOAD INSTRUCTION: Expert techniques for converting an arbitrary write primitive into code execution. Covers every major overwrite target organized by glibc version compatibility: GOT, __malloc_hook, __free_hook, _IO_FILE vtable, __exit_funcs, TLS_dtor_list, _dl_fini, modprobe_path, .fini_array, C++ vtable, and setcontext gadget. This is the "last mile" skill. Base models often target hooks that no longer exist (post-glibc 2.34) or miss pointer mangling requirements.
0. RELATED ROUTING
- heap-exploitation — obtaining the arbitrary write via heap attacks
- format-string-exploitation — obtaining the arbitrary write via %n
- stack-overflow-and-rop — stack-based write primitives
- binary-protection-bypass — which targets are available given protection configuration
- heap-exploitation IO_FILE_EXPLOITATION.md — deep _IO_FILE structure exploitation
1. TARGET SELECTION BY GLIBC VERSION
| Target | glibc < 2.24 | 2.24–2.33 | ≥ 2.34 | Required Knowledge |
|---|---|---|---|---|
| GOT overwrite | OK (Partial RELRO) | OK (Partial RELRO) | OK (Partial RELRO) | Binary base |
__malloc_hook |
OK | OK | Removed | libc base |
__free_hook |
OK | OK | Removed | libc base |
__realloc_hook |
OK | OK | Removed | libc base |
_IO_FILE vtable (direct) |
OK | Vtable range check | Vtable range check | libc base + heap |
_IO_FILE via _IO_str_jumps |
N/A | OK (2.24–2.27) | Patched | libc base + heap |
_IO_FILE via _IO_wfile_jumps |
N/A | OK (≥ 2.28) | OK | libc base + heap |
__exit_funcs |
OK | OK | OK | libc base + pointer guard |
TLS_dtor_list |
N/A | N/A | OK | TLS addr + pointer guard |
_dl_fini / link_map |
OK | OK | OK | ld.so base |
modprobe_path (kernel) |
OK | OK | OK | Kernel base |
.fini_array |
OK | OK | OK | Binary base (if writable) |
| C++ vtable | OK | OK | OK | Object address + heap |
setcontext gadget |
OK | OK (changed in 2.29) | OK | libc base |
| Stack return address | Always | Always | Always | Stack address |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 1mo ago First seen · 362 lines · 80 tokens per session scan B e01c2f2b665d
arbitrary-write-to-rce is a skill published in the GitHub repository SecurityTalent/bugskill-ai (13 stars, last pushed 21d ago), licensed MIT. It adds 80 tokens to every session and 3,783 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it B with 1 finding (unrestricted tool access). It is 100% identical to arbitrary-write-to-rce, differing in 0 lines, and is treated as a copy.
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