CVE-2021-30307
📋 TL;DR
This vulnerability in Qualcomm Snapdragon chipsets allows denial of service attacks due to improper DNS response validation. When DNS clients request PTR, NAPTR, or SRV query types, malicious responses can crash the system. Affected products include Snapdragon Auto, Compute, Connectivity, Consumer IoT, and Industrial IoT platforms.
💻 Affected Systems
- Snapdragon Auto
- Snapdragon Compute
- Snapdragon Connectivity
- Snapdragon Consumer IOT
- Snapdragon Industrial IOT
📦 What is this software?
Sd7c Firmware by Qualcomm
⚠️ Risk & Real-World Impact
Worst Case
Complete system crash or reboot causing service disruption in automotive, industrial, or IoT devices, potentially affecting safety-critical systems.
Likely Case
Temporary denial of service causing device reboots or network connectivity loss in affected IoT and embedded systems.
If Mitigated
Minimal impact with proper network segmentation and DNS filtering preventing malicious responses from reaching vulnerable devices.
🎯 Exploit Status
Exploitation requires ability to send malicious DNS responses to vulnerable devices, which typically means controlling DNS server or performing DNS poisoning.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Qualcomm January 2022 security bulletin for specific chipset updates
Vendor Advisory: https://www.qualcomm.com/company/product-security/bulletins/january-2022-bulletin
Restart Required: Yes
Instructions:
1. Contact device manufacturer for firmware updates. 2. Apply Qualcomm-provided patches for affected chipsets. 3. Reboot affected devices after patching.
🔧 Temporary Workarounds
DNS Response Filtering
allConfigure DNS servers to filter or block malicious responses to PTR, NAPTR, and SRV queries
Network Segmentation
allIsolate vulnerable devices from untrusted networks and DNS servers
🧯 If You Can't Patch
- Implement strict DNS server controls and monitoring
- Use network firewalls to restrict DNS traffic to trusted sources only
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against Qualcomm security bulletin; devices using affected Snapdragon chipsets without January 2022 patches are vulnerableCheck Version:
Device-specific commands vary by manufacturer; consult device documentation for firmware version checkingVerify Fix Applied:
Verify firmware version has been updated to include January 2022 security patches from Qualcomm📡 Detection & Monitoring
Log Indicators:
- Unexpected device reboots
- DNS client crashes
- Increased DNS error rates for PTR/NAPTR/SRV queries
Network Indicators:
- Unusual DNS response patterns
- DNS traffic spikes to affected devices
- Malformed DNS packets
SIEM Query:
DNS queries with type PTR, NAPTR, or SRV followed by device crash/reboot events