CVE-2021-35081
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code or cause denial of service via buffer overflow in Qualcomm Snapdragon chipsets. It affects devices using vulnerable Snapdragon components during IBSS (ad-hoc) Wi-Fi sessions. The vulnerability is in the wireless firmware handling of SSID length validation.
💻 Affected Systems
- Snapdragon Auto
- Snapdragon Compute
- Snapdragon Connectivity
- Snapdragon Consumer Electronics Connectivity
- Snapdragon Industrial IOT
- Snapdragon Mobile
- Snapdragon Voice & Music
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with kernel privileges leading to complete device compromise, data theft, or persistent backdoor installation.
Likely Case
Device crash/reboot (denial of service) or limited code execution within wireless subsystem context.
If Mitigated
No impact if patched or if IBSS mode is disabled; limited to denial of service if exploit fails.
🎯 Exploit Status
Exploitation requires Wi-Fi proximity and IBSS session initiation; no authentication needed to trigger the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware updates released in April 2022 security bulletin
Vendor Advisory: https://www.qualcomm.com/company/product-security/bulletins/april-2022-bulletin
Restart Required: Yes
Instructions:
1. Check with device manufacturer for firmware updates. 2. Apply Qualcomm-provided firmware patches. 3. Reboot device after update. 4. Verify patch installation through version checks.
🔧 Temporary Workarounds
Disable IBSS/Ad-hoc Wi-Fi Mode
allPrevents exploitation by disabling the vulnerable IBSS functionality.
# Android: Use developer settings or device policies to disable ad-hoc networking
# Linux: iwconfig wlan0 mode managed
# Windows: Disable 'Connect to ad-hoc networks' in Wi-Fi settings
Network Segmentation
allIsolate vulnerable devices from untrusted Wi-Fi networks.
# Use firewall rules to restrict Wi-Fi network access
# Configure network policies to prevent ad-hoc connections
🧯 If You Can't Patch
- Disable Wi-Fi entirely on critical systems if not needed
- Implement physical security controls to prevent unauthorized Wi-Fi proximity
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against Qualcomm's April 2022 security bulletin; devices with unpatched firmware are vulnerable.Check Version:
# Android: Settings > About Phone > Build Number/Kernel Version
# Linux: dmesg | grep -i qualcomm
# General: Check device manufacturer's firmware update documentationVerify Fix Applied:
Verify firmware version has been updated post-April 2022; check with manufacturer for specific patch verification.📡 Detection & Monitoring
Log Indicators:
- Unexpected device reboots/crashes
- Wi-Fi subsystem errors in system logs
- IBSS session initiation failures
Network Indicators:
- Unusual IBSS network traffic patterns
- Malformed beacon/probe response frames detected
SIEM Query:
source="*syslog*" AND ("IBSS" OR "ad-hoc") AND ("crash" OR "overflow" OR "exception")