CVE-2023-35849
📋 TL;DR
CVE-2023-35849 is an improper validation vulnerability in VirtualSquare picoTCP (PicoTCP-NG) where the library fails to properly check header sizes, potentially allowing access to data outside packet boundaries. This affects all systems using picoTCP versions through 2.1 for network communication. Attackers could exploit this to cause denial of service or potentially execute arbitrary code.
💻 Affected Systems
- VirtualSquare picoTCP
- PicoTCP-NG
📦 What is this software?
Picotcp by Virtualsquare
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data exfiltration, or persistent backdoor installation.
Likely Case
Denial of service through application crashes or system instability, potentially leading to service disruption.
If Mitigated
Limited impact with proper network segmentation, minimal exposure, and monitoring in place.
🎯 Exploit Status
Exploitation requires sending specially crafted network packets to vulnerable systems. No public exploit code is currently available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after commit 4b9a16764f2b12b611de9c34a50b4713d10ca401
Vendor Advisory: https://github.com/virtualsquare/picotcp/commit/4b9a16764f2b12b611de9c34a50b4713d10ca401
Restart Required: Yes
Instructions:
1. Update picoTCP to latest version from GitHub repository. 2. Recompile any applications using picoTCP. 3. Restart affected services or systems.
🔧 Temporary Workarounds
Network Segmentation
allIsolate systems using picoTCP from untrusted networks
Firewall Rules
linuxRestrict network access to picoTCP services
iptables -A INPUT -p tcp --dport [PORT] -j DROP
iptables -A INPUT -p udp --dport [PORT] -j DROP
🧯 If You Can't Patch
- Implement strict network access controls and segmentation
- Deploy intrusion detection systems to monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check picoTCP version in source code or compiled libraries. Versions ≤2.1 are vulnerable.Check Version:
grep -r "PICO_VERSION" in source code or check library metadataVerify Fix Applied:
Verify picoTCP version includes commit 4b9a16764f2b12b611de9c34a50b4713d10ca401 or later.📡 Detection & Monitoring
Log Indicators:
- Application crashes
- Memory access violation errors
- Unexpected network packet handling
Network Indicators:
- Unusual packet patterns targeting picoTCP services
- Traffic with malformed headers
SIEM Query:
source="*picoTCP*" AND (event_type="crash" OR event_type="memory_violation")