CVE-2019-17508
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary commands on affected D-Link routers via command injection in the DEVICE.TIME.php script. Attackers can gain full control of the device by injecting commands through the $SERVER variable. Users of DIR-859 and DIR-850 routers with vulnerable firmware versions are affected.
💻 Affected Systems
- D-Link DIR-859
- D-Link DIR-850
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router allowing attackers to intercept all network traffic, install persistent malware, pivot to internal network devices, and use the router as part of a botnet.
Likely Case
Router takeover leading to DNS hijacking, credential theft from network traffic, and installation of cryptocurrency miners or other malware.
If Mitigated
Limited impact if router is behind firewall with restricted WAN access, though internal attackers could still exploit.
🎯 Exploit Status
Exploit requires no authentication and has simple command injection payloads. Multiple public PoCs exist.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: DIR-859 firmware 1.07 or later, DIR-850 firmware 1.14 or later
Vendor Advisory: https://support.dlink.com/security/
Restart Required: Yes
Instructions:
1. Log into router web interface. 2. Navigate to Administration > Firmware Update. 3. Download latest firmware from D-Link support site. 4. Upload and apply firmware update. 5. Reboot router after update completes.
🔧 Temporary Workarounds
Disable Remote Management
allPrevents external attackers from accessing the vulnerable web interface
Restrict LAN Access
allUse firewall rules to restrict which devices can access the router's web interface
🧯 If You Can't Patch
- Replace affected routers with newer models or different vendors
- Place routers behind dedicated firewalls with strict inbound/outbound rules
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface under Tools > System InfoCheck Version:
curl -s http://router-ip/DEVICE.TIME.php | grep versionVerify Fix Applied:
Verify firmware version is DIR-859 1.07+ or DIR-850 1.14+ after update📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /DEVICE.TIME.php with shell metacharacters
- Commands like 'wget', 'curl', or 'nc' in web logs
Network Indicators:
- Outbound connections from router to suspicious IPs
- DNS queries to malicious domains
SIEM Query:
source="router-logs" AND uri="/DEVICE.TIME.php" AND (request CONTAINS "$" OR request CONTAINS ";" OR request CONTAINS "|")