CVE-2020-17528
📋 TL;DR
This vulnerability allows attackers to perform out-of-bounds writes in Apache NuttX's TCP stack by supplying malicious urgent data pointer offsets in TCP packets. This can lead to memory corruption, potentially enabling remote code execution or denial of service. All systems running Apache NuttX versions up to and including 9.1.0 and 10.0.0 are affected.
💻 Affected Systems
- Apache NuttX (incubating)
📦 What is this software?
Nuttx by Apache
Nuttx by Apache
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with root/system privileges leading to complete system compromise
Likely Case
Denial of service through system crashes or memory corruption leading to instability
If Mitigated
Limited impact if network segmentation prevents external access to vulnerable systems
🎯 Exploit Status
Exploitation requires crafting TCP packets with malicious urgent data pointer offsets
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 9.1.0 and 10.0.0
Vendor Advisory: https://lists.apache.org/thread.html/r7f4215aba288660b41b7e731b6262c8275fa476e91e527a74d2888ea%40%3Cdev.nuttx.apache.org%3E
Restart Required: Yes
Instructions:
1. Update Apache NuttX to a version after 9.1.0/10.0.0
2. Recompile and redeploy the operating system
3. Restart affected systems
🔧 Temporary Workarounds
Disable TCP urgent data processing
allModify NuttX configuration to disable processing of TCP urgent data pointers
Edit nuttx/.config and set CONFIG_NET_TCPURGDATA=n
Network segmentation
allIsolate vulnerable systems from untrusted networks
🧯 If You Can't Patch
- Implement strict network access controls to limit TCP traffic to trusted sources only
- Deploy network-based intrusion prevention systems to detect and block malicious TCP packets
🔍 How to Verify
Check if Vulnerable:
Check NuttX version with 'uname -a' or examine build configuration for version numbersCheck Version:
uname -a | grep -i nuttxVerify Fix Applied:
Verify NuttX version is newer than 9.1.0/10.0.0 and check that CONFIG_NET_TCPURGDATA is disabled if using workaround📡 Detection & Monitoring
Log Indicators:
- System crashes
- Memory corruption errors
- TCP connection anomalies
Network Indicators:
- TCP packets with unusual urgent data pointer offsets
- Malformed TCP packets targeting NuttX systems
SIEM Query:
source="network_traffic" AND tcp_flags.urg=1 AND (tcp_urgent_pointer > packet_length OR tcp_urgent_pointer < 0)🔗 References
- http://www.openwall.com/lists/oss-security/2020/12/09/4
- https://lists.apache.org/thread.html/r7f4215aba288660b41b7e731b6262c8275fa476e91e527a74d2888ea%40%3Cdev.nuttx.apache.org%3E
- https://lists.apache.org/thread.html/r7f4215aba288660b41b7e731b6262c8275fa476e91e527a74d2888ea%40%3Cdev.nuttx.apache.org%3E
- http://www.openwall.com/lists/oss-security/2020/12/09/4
- https://lists.apache.org/thread.html/r7f4215aba288660b41b7e731b6262c8275fa476e91e527a74d2888ea%40%3Cdev.nuttx.apache.org%3E
- https://lists.apache.org/thread.html/r7f4215aba288660b41b7e731b6262c8275fa476e91e527a74d2888ea%40%3Cdev.nuttx.apache.org%3E
