CVE-2024-41593
📋 TL;DR
CVE-2024-41593 is a critical heap-based buffer overflow vulnerability in DrayTek Vigor310 devices that allows remote attackers to execute arbitrary code. The vulnerability occurs due to sign-extension issues in the ft_payload_dns() function, enabling remote code execution without authentication. Organizations using affected DrayTek Vigor310 devices are at risk of complete device compromise.
💻 Affected Systems
- DrayTek Vigor310
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device takeover allowing attacker to install persistent backdoors, pivot to internal networks, intercept all network traffic, and use device as botnet node.
Likely Case
Remote code execution leading to device compromise, credential theft, network reconnaissance, and potential lateral movement to connected systems.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering, but still vulnerable to internal threats or compromised adjacent systems.
🎯 Exploit Status
Public research includes technical details and exploitation vectors. The vulnerability requires sending specially crafted DNS packets to the device.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check DrayTek for latest firmware updates beyond 4.3.2.6
Vendor Advisory: https://www.draytek.com/support/security-advisory/
Restart Required: Yes
Instructions:
1. Log into Vigor310 web interface. 2. Navigate to System Maintenance > Firmware Upgrade. 3. Download latest firmware from DrayTek support portal. 4. Upload and apply firmware update. 5. Reboot device after update completes.
🔧 Temporary Workarounds
DNS Traffic Filtering
allBlock or filter inbound DNS traffic to Vigor310 devices from untrusted sources
Network Segmentation
allIsolate Vigor310 devices in separate VLAN with restricted access
🧯 If You Can't Patch
- Remove internet-facing exposure by placing devices behind firewalls with strict inbound filtering
- Implement network monitoring for anomalous DNS traffic patterns to Vigor310 devices
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface: System Maintenance > Firmware Information. If version is 4.3.2.6 or earlier, device is vulnerable.Check Version:
No CLI command - use web interface at System Maintenance > Firmware InformationVerify Fix Applied:
Verify firmware version is updated beyond 4.3.2.6 and test DNS functionality remains operational.📡 Detection & Monitoring
Log Indicators:
- Unusual DNS query patterns
- Firmware modification attempts
- Unexpected process execution
Network Indicators:
- Malformed DNS packets to Vigor310 devices
- Unexpected outbound connections from Vigor310
SIEM Query:
source_ip="Vigor310_IP" AND (protocol="DNS" AND packet_size>threshold) OR destination_ip="Vigor310_IP" AND protocol="DNS" AND payload_contains_suspicious_patterns