Menu

Individual skill

crypto

Web crypto exploitation — padding-oracle (Vaudenay), AES-CBC bit-flipping / IV manipulation, AES-ECB pattern attacks (cut-and-paste, prefix/suffix recovery), HMAC bypass, hash-length extension, JWT alg confusion. Covers detection signals, working in-file Python harnesses (concurrent.futures, timeout=5, python3 -u, bounded request budget), and the confirm-oracle gate that must fire before iteration.

packages/decepticon/decepticon/skills/standard/exploit/web/crypto/SKILL.md

Read pinned source

Source commit cc6044561ff32188dc0aa899bcc7d3666ffcfd1c

What was checked

Matches the observed repository HEAD
Yes
Scanner rules are current
Yes
Repository scan complete
No
Skill scan complete
No
Observed behavior
Network or broad shell
Last checked
Nov 2, 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)
6,560
Repository last updated
Nov 7, 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

# Web Crypto Exploitation

Exploits applications that misuse symmetric ciphers (CBC/ECB), MACs (HMAC, hash-length extension), or token signers (JWT). The decisive trick is almost always: **find the oracle, prove the oracle is real, then iterate within a hard request budget**. Without the proven oracle the attack burns the cycle.

## Step 0 — Key Discovery (Do Before ANY Network Attack)

**Check if the application key is hardcoded in source.** CTF challenge apps frequently embed keys in source code. If you have filesystem access to the app, run this before any network probe:

```bash
# Find app source in the workspace
find /workspace -name "*.py" -o -name "*.js" -o -name "*.rb" -o -name "*.php" 2>/dev/null | head -20

# Grep for hardcoded keys
grep -rn 'AES_KEY\|SECRET_KEY\|key\s*=\s*[b'"'"'"'"'"'"'"'"']\|password\s*=' /workspace/*/app/ 2>/dev/null | head -20