CVE-2019-15656
📋 TL;DR
This vulnerability in D-Link DSL-2875AL and DSL-2877AL routers allows attackers to retrieve administrator credentials via a simple crafted HTTP request to the web management interface. It affects users of these specific D-Link router models who have not applied security patches. The information disclosure occurs through exposed username_v and password_v variables in index.asp.
💻 Affected Systems
- D-Link DSL-2875AL
- D-Link DSL-2877AL
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain full administrative access to the router, enabling them to reconfigure network settings, intercept traffic, install malware, or use the device as part of a botnet.
Likely Case
Attackers obtain router admin credentials and use them to change DNS settings, redirect traffic, or monitor network activity.
If Mitigated
With proper network segmentation and firewall rules, the impact is limited to the router itself without compromising internal network resources.
🎯 Exploit Status
The exploit requires only a simple HTTP request to the vulnerable endpoint without authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version after 1.00.05
Vendor Advisory: https://www.dlink.com/en/security-bulletin
Restart Required: Yes
Instructions:
1. Log into D-Link support portal. 2. Download latest firmware for your specific model. 3. Access router web interface. 4. Navigate to Maintenance > Firmware Upgrade. 5. Upload and apply the new firmware. 6. Wait for automatic reboot.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to the web management interface
Restrict Management Interface Access
allConfigure firewall rules to only allow management access from trusted IP addresses
🧯 If You Can't Patch
- Replace affected routers with updated models or different vendors
- Implement network segmentation to isolate router management traffic
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface: System > Status > Firmware VersionCheck Version:
curl -s http://router-ip/status.asp | grep -i firmwareVerify Fix Applied:
Confirm firmware version is newer than 1.00.05 and test that accessing index.asp with crafted parameters no longer returns credentials📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to index.asp with crafted parameters
- Multiple failed login attempts followed by successful login from new IP
Network Indicators:
- HTTP requests to router IP on port 80/443 containing username_v or password_v parameters
- Unusual outbound traffic from router
SIEM Query:
source="router_logs" AND (uri="*index.asp*" AND (param="*username_v*" OR param="*password_v*"))