CVE-2021-28031
📋 TL;DR
This vulnerability in the Rust scratchpad crate allows double-free memory corruption when a user-provided function panics during move_elements operations. Attackers could exploit this to execute arbitrary code or cause denial of service. Any Rust application using vulnerable versions of the scratchpad crate is affected.
💻 Affected Systems
- Rust applications using scratchpad crate
📦 What is this software?
Scratchpad by Scratchpad Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application crash or denial of service due to memory corruption.
If Mitigated
Limited impact with proper memory isolation and exploit mitigations like ASLR and stack canaries.
🎯 Exploit Status
Exploitation requires triggering a panic in user-provided function during move_elements operation. Proof-of-concept demonstrates crash but full RCE requires additional memory manipulation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: scratchpad 1.3.1
Vendor Advisory: https://rustsec.org/advisories/RUSTSEC-2021-0030.html
Restart Required: Yes
Instructions:
1. Update Cargo.toml to require scratchpad >= 1.3.1. 2. Run 'cargo update' to fetch new version. 3. Rebuild and redeploy application. 4. Restart affected services.
🔧 Temporary Workarounds
Avoid panic-prone callbacks
allModify code to prevent panics in user-provided functions passed to move_elements
Use catch_unwind
allWrap move_elements calls in std::panic::catch_unwind to prevent double-free on panic
🧯 If You Can't Patch
- Isolate application with strict memory limits and containerization
- Implement input validation and sanitization to prevent triggering vulnerable code paths
🔍 How to Verify
Check if Vulnerable:
Check Cargo.lock or run 'cargo tree | grep scratchpad' to see installed versionCheck Version:
grep scratchpad Cargo.lock | head -1Verify Fix Applied:
Confirm scratchpad version is 1.3.1 or higher in Cargo.lock📡 Detection & Monitoring
Log Indicators:
- Application crashes with segmentation faults
- Memory corruption errors in Rust panic logs
- Unexpected process termination
Network Indicators:
- Unusual outbound connections after crash
- Exploit attempt patterns in input data
SIEM Query:
process.name: "your_rust_app" AND (event.type: "crash" OR error.message: "*double free*" OR error.message: "*segmentation fault*")