CVE-2020-21572
📋 TL;DR
A buffer overflow vulnerability in the src_parser_trans_stage_1_2_3 function of trgil gilcc allows attackers to cause denial of service by crashing the application. This affects users of gilcc before commit 803969389ca9c06237075a7f8eeb1a19e6651759.
💻 Affected Systems
- trgil gilcc
📦 What is this software?
Gilcc by Gilcc Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise if the buffer overflow can be manipulated to execute arbitrary code.
Likely Case
Denial of service through application crash, disrupting service availability.
If Mitigated
Minimal impact with proper input validation and memory protections enabled.
🎯 Exploit Status
Exploitation requires crafting specific input to trigger the buffer overflow, but no public exploit code has been documented.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Commit 803969389ca9c06237075a7f8eeb1a19e6651759 and later
Vendor Advisory: https://github.com/trgil/gilcc/commit/803969389ca9c06237075a7f8eeb1a19e6651759
Restart Required: Yes
Instructions:
1. Update to the latest version of gilcc from the official repository. 2. Rebuild the application from source. 3. Restart any services using gilcc.
🔧 Temporary Workarounds
Input Validation
allImplement strict input validation to prevent malicious data from reaching the vulnerable function.
Memory Protection
linuxEnable ASLR and DEP/Stack Canaries if supported by the platform to mitigate exploitation.
gcc -fstack-protector-all -D_FORTIFY_SOURCE=2 -O2
🧯 If You Can't Patch
- Isolate the vulnerable system from untrusted networks and users.
- Monitor for abnormal crashes or memory usage patterns indicative of exploitation attempts.
🔍 How to Verify
Check if Vulnerable:
Check the git commit hash of your gilcc installation; if earlier than 803969389ca9c06237075a7f8eeb1a19e6651759, it is vulnerable.Check Version:
git log --oneline -1Verify Fix Applied:
Verify the commit hash matches or is later than 803969389ca9c06237075a7f8eeb1a19e6651759 after updating.📡 Detection & Monitoring
Log Indicators:
- Application crashes, segmentation faults, or abnormal termination logs
Network Indicators:
- Unusual input patterns or large payloads sent to the service
SIEM Query:
source="application.log" AND ("segmentation fault" OR "buffer overflow" OR "crash")