CVE-2021-1981
📋 TL;DR
This vulnerability is a buffer over-read in Qualcomm Snapdragon chipsets due to improper size checking of Bearer capability information elements in MT setup requests from networks. It affects multiple Snapdragon platforms including Auto, Compute, Connectivity, Consumer IoT, Industrial IoT, and Mobile. Attackers could potentially read sensitive data from adjacent memory locations.
💻 Affected Systems
- Snapdragon Auto
- Snapdragon Compute
- Snapdragon Connectivity
- Snapdragon Consumer IOT
- Snapdragon Industrial IOT
- Snapdragon Mobile
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, data exfiltration, or persistent backdoor installation on affected devices.
Likely Case
Information disclosure through memory read, potentially exposing sensitive data or cryptographic keys stored in adjacent memory.
If Mitigated
Denial of service or system instability if memory access causes crashes, but no data compromise.
🎯 Exploit Status
Exploitation requires sending specially crafted network packets to trigger the buffer over-read. No public exploits known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Qualcomm security bulletin November 2021 and device manufacturer updates
Vendor Advisory: https://www.qualcomm.com/company/product-security/bulletins/november-2021-bulletin
Restart Required: Yes
Instructions:
1. Check with device manufacturer for firmware/software updates. 2. Apply Qualcomm-provided patches through OEM channels. 3. Reboot device after update. 4. Verify patch installation.
🔧 Temporary Workarounds
Network segmentation
allIsolate affected devices from untrusted networks to prevent exploitation attempts.
Firewall rules
allBlock unnecessary network protocols to affected devices at perimeter.
🧯 If You Can't Patch
- Segment affected devices in isolated network zones with strict access controls
- Implement network monitoring for anomalous MT setup requests or memory access patterns
🔍 How to Verify
Check if Vulnerable:
Check device firmware/software version against manufacturer security bulletins. Use Qualcomm diagnostic tools if available.Check Version:
Device-specific commands vary by manufacturer; typically 'adb shell getprop ro.build.version' for Android devicesVerify Fix Applied:
Verify installed firmware version matches patched versions from manufacturer. Test with security scanning tools if available.📡 Detection & Monitoring
Log Indicators:
- Baseband/module crash logs
- Memory access violation logs
- Unexpected MT setup request patterns
Network Indicators:
- Anomalous network packets targeting baseband interfaces
- Unusual MT setup request patterns
SIEM Query:
Search for baseband crash events, memory violation alerts, or network anomalies to affected device IPs