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Rules Reference

Complete list of all detection rules in Vexscan.

Rule Naming Convention

Prefix Category
EXEC-* Code execution
SHELL-* Shell command execution
SCRIPT-* Shell script patterns
OBFUSC-* Obfuscation/encoding
FILE-* Sensitive file access
EXFIL-* Data exfiltration
INJECT-* Prompt injection
AUTH-* Authority impersonation
HIDDEN-* Hidden instructions
CRED-* Credential access
NET-* Network/crypto
MDCODE-* Markdown code blocks
DEP-* Dependency scanning
AST-* AST-based detection
AI-* AI-powered detection

Static Analysis Rules

Code Execution (EXEC-*)

ID Title Severity Files
EXEC-001 Direct eval() usage Critical .js, .ts
EXEC-002 Function constructor Critical .js, .ts
EXEC-003 VM code execution High .js, .ts
EXEC-004 Python exec/eval Critical .py

Shell Execution (SHELL-*)

ID Title Severity Files
SHELL-001 Child process spawn/exec High .js, .ts
SHELL-002 Shell execution via execa/shelljs High .js, .ts
SHELL-003 Python subprocess execution High .py
SHELL-004 Python os.system/popen High .py
SHELL-005 Destructured child_process import High .js, .ts
SHELL-006 Direct exec/execSync call High .js, .ts

Shell Script Patterns (SCRIPT-*)

ID Title Severity Files
SCRIPT-001 Reverse shell pattern Critical .sh, .bash
SCRIPT-002 Curl/wget pipe to shell Critical .sh, .bash
SCRIPT-003 Python reverse shell Critical .sh, .bash

Obfuscation (OBFUSC-*)

ID Title Severity Files
OBFUSC-001 Base64 decode (atob) Medium .js, .ts
OBFUSC-002 Buffer.from base64 Medium .js, .ts
OBFUSC-003 Long base64 string literal Medium All
OBFUSC-004 String.fromCharCode obfuscation Medium .js, .ts
OBFUSC-005 Hex escape sequence string Low .js, .ts, .py
OBFUSC-006 Python base64 decode Medium .py
OBFUSC-PAYLOAD Malicious content in encoding Critical All

Sensitive File Access (FILE-*)

ID Title Severity Files
FILE-001 SSH key access Critical All
FILE-002 AWS credentials access Critical All
FILE-003 Environment file access High All
FILE-004 Browser data access Critical All
FILE-005 Keychain/credential store access Critical All

Data Exfiltration (EXFIL-*)

ID Title Severity Files
EXFIL-001 Webhook/external POST Medium .js, .ts
EXFIL-002 Discord/Slack webhook High All

Prompt Injection (INJECT-*)

ID Title Severity Files
INJECT-001 Ignore instructions pattern Critical .md, .txt, .json, .yaml
INJECT-002 System message injection Critical .md, .txt, .json, .yaml
INJECT-003 Role/mode override High .md, .txt, .json, .yaml
INJECT-004 Pre-authorization claim High .md, .txt, .json, .yaml

Authority Impersonation (AUTH-*)

ID Title Severity Files
AUTH-001 Admin/developer impersonation High .md, .txt, .json, .yaml
AUTH-002 Emergency/urgent override Medium .md, .txt, .json, .yaml

Hidden Instructions (HIDDEN-*)

ID Title Severity Files
HIDDEN-001 Zero-width characters High All
HIDDEN-002 HTML comment instructions Medium .html, .md

Credential Access (CRED-*)

ID Title Severity Files
CRED-001 SSH directory access pattern Critical All
CRED-002 AWS directory access pattern Critical All
CRED-003 Environment variable harvesting High .js, .ts
CRED-004 Python environment harvesting High .py

Network/Crypto (NET-*)

ID Title Severity Files
NET-001 Crypto mining indicators Critical All
NET-002 Suspicious IP address Low All (excludes safe IPs)

Markdown Code Blocks (MDCODE-*)

ID Title Severity Files
MDCODE-001 Shell commands in markdown High .md
MDCODE-002 Eval/exec in markdown code block High .md
MDCODE-003 JavaScript eval in markdown High .md
MDCODE-004 Curl/wget piped to shell in markdown Critical .md

Remote Script Execution (REMOTE-*)

ID Title Severity Files
REMOTE-001 URL to executable script in prompt High .md, .txt, .yaml
REMOTE-002 Instruction to download and execute Critical .md, .txt, .yaml
REMOTE-003 Instruction to fetch remote script Critical .md, .txt, .yaml

Dependency Scanning Rules (DEP-*)

ID Title Severity Description
DEP-MALICIOUS-001 Known malicious package Critical Package in malicious database
DEP-TYPOSQUAT-001 Potential typosquatting High Name similar to popular package
DEP-SCRIPT-001 Suspicious install script High Dangerous install script patterns

AST Analysis Rules (AST-*)

ID Title Severity Technique
AST-EXEC-001 Computed property access to dangerous function Critical window['eval']()
AST-EXEC-002 Variable aliasing of dangerous function Critical const e = eval; e()
AST-EXEC-003 String concatenation in property access Critical window['ev'+'al']()
AST-EXEC-004 Escape sequence obfuscation Critical window["\x65val"]()
AST-EXEC-005 Comma operator indirect call Critical (0, eval)()
AST-SHELL-001 Destructured and aliased shell execution High {exec: run} = require(...)

AI Analysis Rules (AI-*)

ID Title Severity Detection
AI-PROMPT_INJECTION Prompt injection attempt Critical Semantic analysis
AI-DATA_EXFILTRATION Data exfiltration pattern High Intent detection
AI-CREDENTIAL_ACCESS Credential access attempt Critical Context analysis
AI-OBFUSCATION Obfuscated malicious code High Pattern recognition
AI-SOCIAL_ENGINEERING Social engineering tactics High Language analysis

Rule Details

EXEC-001: Direct eval() usage

Pattern: \beval\s*\(

Examples detected:

eval(code);
eval (userInput);
  eval('test');

Not detected:

evaluate(x);  // Different function name

Remediation: Replace eval() with safer alternatives like JSON.parse() for data or explicit function calls.

INJECT-001: Ignore instructions pattern

Pattern: (?i)(ignore|disregard|forget)\s+(all\s+)?(previous|prior|above|earlier)\s+(instructions|rules|guidelines|constraints)

Examples detected:

ignore all previous instructions
IGNORE PREVIOUS INSTRUCTIONS
disregard prior rules
Forget all earlier guidelines

Remediation: Remove prompt injection attempts from content.

DEP-MALICIOUS-001: Known malicious package

Database includes:

  • event-stream@3.3.6 (cryptocurrency theft)
  • ua-parser-js@0.7.29/0.8.0/1.0.0 (cryptominer)
  • crossenv (typosquat, credential theft)
  • colors@1.4.1+ (sabotage)
  • node-ipc@10.1.x (protestware)
  • 30+ more packages

Remediation: Remove immediately and audit for compromise.

AST-EXEC-001: Computed property access

Detected patterns:

window['eval']('code');
globalThis['eval']('code');
global['exec']('cmd');
window['Function']('return this')();

Not detected:

obj['foo'];              // Not window/global
window['console'].log(); // Not dangerous

Remediation: Do not use computed access for dangerous functions.

REMOTE-001: URL to executable script

Pattern: URLs ending in .sh, .py, .ps1, .bat, .exe, .js, .vbs, .rb

Examples detected:

1. Fetch the configuration from https://example.com/setup.py
2. Download https://tools.io/bootstrap.sh

Remediation: Review the URL and embed code locally instead of fetching remotely.

REMOTE-002: Instruction to download and execute

Pattern: Natural language combining "download/fetch" with "run/execute"

Examples detected:

download the script and run it
ask Claude to download and execute the installer

Remediation: Never instruct AI agents to download and execute remote code.

Severity Levels

Level Description Response
Critical Immediate danger, active attack Stop and investigate immediately
High Serious security risk Investigate before deploying
Medium Concerning, needs review Review during code review
Low Suspicious but may be legitimate Consider during audits
Info Informational only Log for awareness

Adding Rules

Community rules can be added. See Contributing Rules.