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<!-- Licensed under AGPL-3.0 — see LICENSE file for details. -->
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---
name: exploiting-signal-handler-vulnerabilities
description: >-
  Exploit unsafe signal handler implementations including async-signal-unsafe function calls, reentrancy issues, and signal race conditions for code execution and privilege escalation.
domain: cybersecurity
subdomain: binary-exploitation
tags:
  - signal-handler
  - reentrancy
  - async-signal
  - unix
version: "1.0"
author: defconxt
license: AGPL-3.0
metadata:
  mitre-attack: ["T1068"]
  frameworks: ["MITRE ATT&CK", "CWE-479"]
  tools: ["gdb", "strace", "pwntools"]
---

# Exploiting Signal Handler Vulnerabilities

## Overview

Exploit unsafe signal handler implementations including async-signal-unsafe function calls, reentrancy issues, and signal race conditions for code execution and privilege escalation.

## Prerequisites

| Tool / Requirement | Details |
|---|---|
| `gdb` | Security tooling |
| `strace` | Security tooling |
| `pwntools` | Security tooling |
| GDB, strace, understanding of POSIX signal semantics | Environment requirement |

## Quick Reference

```bash
# Quick start commands
node scripts/agent.js --help
strace -e signal ./target && objdump -d ./target | grep signal
```

## Workflow

### Step 1: Identify Signal Handlers

```bash
strace -e signal ./target && objdump -d ./target | grep signal
```

### Step 2: Analyze Handler Safety

```bash
node scripts/agent.js analyze --binary ./target --check signal-safety
```

### Step 3: Exploit Reentrancy Bug

```bash
node scripts/agent.js exploit --binary ./target --signal SIGUSR1
```

## Detection

```yaml
title: Exploiting Signal Handler Vulnerabilities Detection
id: b5d8011d-cb09-464e-80a6-2660a6a18955
status: experimental
description: Detects suspicious activity related to exploiting signal handler vulnerabilities techniques in binary exploitation context
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    CommandLine: "*exploiting*signal*"
  condition: selection
level: critical
tags:
  - attack.t1068
  - attack.execution
falsepositives:
  - Vulnerability scanner testing known exploit signatures
```


**Detection Opportunities**

| Indicator | Source | Detection Logic |
|---|---|---|
| Exploiting Signal Handler Vulnerabilities Detection | windows/process_creation | Sigma rule (critical) |
| ATT&CK Coverage | MITRE ATT&CK | T1068 |

## Verification

- **Verify signal handlers**: `node scripts/agent.js analyze --binary ./target --check signal-safety`
- **Confirm exploitation**: `node scripts/agent.js exploit --binary ./target --signal SIGUSR1`

## References

- MITRE ATT&CK: T1068
- Frameworks: MITRE ATT&CK, CWE-479
- Tools: gdb, strace, pwntools
