CVE-2021-1935
📋 TL;DR
This vulnerability in Qualcomm Snapdragon chipsets allows potential denial of service or arbitrary code execution due to a null pointer dereference during key import operations. It affects multiple Snapdragon product lines including Auto, Compute, Connectivity, Consumer IoT, Industrial IoT, IoT, Voice & Music, and Wearables. Attackers could exploit this to crash affected devices or potentially execute malicious code.
💻 Affected Systems
- Snapdragon Auto
- Snapdragon Compute
- Snapdragon Connectivity
- Snapdragon Consumer IOT
- Snapdragon Industrial IOT
- Snapdragon IoT
- Snapdragon Voice & Music
- Snapdragon Wearables
📦 What is this software?
Sd7c Firmware by Qualcomm
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, data theft, or persistent backdoor installation
Likely Case
Denial of service causing device crashes or instability
If Mitigated
Limited impact with proper network segmentation and access controls
🎯 Exploit Status
Exploitation requires triggering the vulnerable key import function; no public exploits known as of advisory publication
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to device manufacturer updates
Vendor Advisory: https://www.qualcomm.com/company/product-security/bulletins/september-2021-bulletin
Restart Required: Yes
Instructions:
1. Check with device manufacturer for firmware updates. 2. Apply manufacturer-provided patches. 3. Reboot device after patching. 4. Verify patch installation.
🔧 Temporary Workarounds
Disable unnecessary services
allReduce attack surface by disabling unused services that might trigger the vulnerable function
Network segmentation
allIsolate affected devices from untrusted networks
🧯 If You Can't Patch
- Implement strict application allowlisting to prevent malicious apps
- Deploy network monitoring for abnormal device behavior
🔍 How to Verify
Check if Vulnerable:
Check device chipset model and firmware version against manufacturer advisoriesCheck Version:
Device-specific commands vary by manufacturer (e.g., 'getprop ro.build.fingerprint' on Android)Verify Fix Applied:
Verify firmware version matches patched version from manufacturer📡 Detection & Monitoring
Log Indicators:
- Unexpected device crashes
- Kernel panic logs
- Security service failures
Network Indicators:
- Abnormal traffic patterns from IoT devices
- Unexpected service restarts
SIEM Query:
Device logs showing repeated crashes of security-related services