CVE-2021-1924
📋 TL;DR
This vulnerability allows attackers to extract RSA private keys through timing and power side-channel attacks during modular exponentiation in RSA-CRT implementations. It affects Qualcomm Snapdragon chipsets across automotive, compute, IoT, wearables, and networking devices. Successful exploitation could lead to complete compromise of encrypted communications and authentication systems.
💻 Affected Systems
- Snapdragon Auto
- Snapdragon Compute
- Snapdragon Connectivity
- Snapdragon Consumer Electronics Connectivity
- Snapdragon Consumer IOT
- Snapdragon Industrial IOT
- Snapdragon IoT
- Snapdragon Voice & Music
- Snapdragon Wearables
- Snapdragon Wired Infrastructure and Networking
📦 What is this software?
Sd7c Firmware by Qualcomm
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of RSA private keys enabling decryption of all past and future encrypted communications, impersonation of devices/servers, and bypass of authentication mechanisms.
Likely Case
Extraction of RSA private keys from vulnerable devices, leading to decryption of sensitive data and potential credential theft.
If Mitigated
Limited impact if proper cryptographic key rotation and network segmentation are implemented, though keys remain vulnerable to local attackers.
🎯 Exploit Status
Exploitation requires physical access or ability to run code on device to perform side-channel measurements; timing attacks may be possible remotely in some configurations
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Qualcomm security bulletin for specific chipset firmware updates
Vendor Advisory: https://www.qualcomm.com/company/product-security/bulletins/november-2021-bulletin
Restart Required: Yes
Instructions:
1. Check Qualcomm security bulletin for affected chipset versions. 2. Contact device manufacturer for firmware updates. 3. Apply firmware updates provided by OEM. 4. Reboot device after update.
🔧 Temporary Workarounds
Disable RSA-CRT or use alternative cryptography
allConfigure systems to use non-vulnerable cryptographic implementations if supported
System-specific configuration commands vary by platform
Implement constant-time cryptographic operations
allUse software libraries with constant-time RSA implementations to mitigate timing side-channels
Depends on specific platform and cryptographic library
🧯 If You Can't Patch
- Rotate all RSA keys used on affected devices immediately
- Isolate affected devices in network segments with strict access controls
🔍 How to Verify
Check if Vulnerable:
Check device chipset model and firmware version against Qualcomm's affected products listCheck Version:
Platform-specific commands vary; on Android: 'getprop ro.bootloader' or 'cat /proc/cpuinfo'Verify Fix Applied:
Verify firmware version has been updated to patched version from device manufacturer📡 Detection & Monitoring
Log Indicators:
- Unusual cryptographic operations
- Multiple failed authentication attempts followed by successful access
Network Indicators:
- Unexpected RSA key changes
- Anomalous traffic patterns from affected devices
SIEM Query:
Search for device model strings containing affected Snapdragon chipsets combined with authentication anomalies