CVE-2021-22156
📋 TL;DR
An integer overflow vulnerability in the calloc() function of QNX runtime libraries allows attackers to cause denial of service or execute arbitrary code. Affects BlackBerry QNX SDP 6.5.0SP1 and earlier, QNX OS for Medical 1.1 and earlier, and QNX OS for Safety 1.0.1 and earlier.
💻 Affected Systems
- BlackBerry QNX Software Development Platform
- QNX OS for Medical
- QNX OS for Safety
📦 What is this software?
Qnx Os For Safety by Blackberry
Qnx Software Development Platform by Blackberry
Qnx Software Development Platform by Blackberry
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with root privileges leading to complete system compromise
Likely Case
Denial of service through application crashes or memory corruption
If Mitigated
Limited impact if systems are isolated and have memory protection mechanisms
🎯 Exploit Status
Integer overflow in memory allocation function requires specific conditions but can be triggered through crafted inputs
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: QNX SDP 6.5.0SP2 and later, QNX OS for Medical 1.2, QNX OS for Safety 1.0.2
Vendor Advisory: https://support.blackberry.com/kb/articleDetail?articleNumber=000082334
Restart Required: Yes
Instructions:
1. Download updated runtime libraries from BlackBerry support. 2. Replace affected libc libraries. 3. Rebuild applications with patched libraries. 4. Restart affected systems.
🔧 Temporary Workarounds
Memory allocation limits
allImplement custom memory allocation wrappers with bounds checking
Implement custom calloc wrapper with overflow checks before allocation
Address Space Layout Randomization
linuxEnable ASLR to make exploitation more difficult
echo 2 > /proc/sys/kernel/randomize_va_space
🧯 If You Can't Patch
- Isolate affected systems from untrusted networks
- Implement strict input validation and memory usage monitoring
🔍 How to Verify
Check if Vulnerable:
Check QNX version with 'uname -a' and compare against affected versionsCheck Version:
uname -aVerify Fix Applied:
Verify libc library version matches patched version and test memory allocation functions📡 Detection & Monitoring
Log Indicators:
- Application crashes with memory corruption errors
- Abnormal memory allocation patterns
Network Indicators:
- Unexpected network connections from QNX systems
- Traffic to/from QNX services with malformed data
SIEM Query:
source="qnx_systems" AND (event_type="crash" OR memory_allocation>threshold)🔗 References
- https://support.blackberry.com/kb/articleDetail?articleNumber=000082334
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-qnx-TOxjVPdL
- https://support.blackberry.com/kb/articleDetail?articleNumber=000082334
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-qnx-TOxjVPdL
