CVE-2020-27539
📋 TL;DR
This vulnerability is a heap buffer overflow in the custom HTTP parser of the AgentUpdater service in Rostelecom CS-C2SHW IP cameras. It allows remote code execution by sending specially crafted HTTP responses, affecting cameras running firmware version 5.0.082.1. In default configurations, the vulnerable code is not reachable without additional bugs.
💻 Affected Systems
- Rostelecom CS-C2SHW IP Camera
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote attacker gains full control of the camera, enabling persistent access, data exfiltration, or use as a botnet node.
Likely Case
Camera compromise leading to unauthorized access to video feeds, denial of service, or lateral movement within the network.
If Mitigated
Limited impact due to default HTTPS-only configuration requiring additional vulnerabilities for exploitation.
🎯 Exploit Status
Exploitation requires bypassing default HTTPS restriction through additional vulnerabilities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check vendor website for firmware updates. 2. Download latest firmware. 3. Upload via camera web interface. 4. Reboot camera.
🔧 Temporary Workarounds
Network Segmentation
allIsolate cameras from internet and restrict internal network access.
Disable AgentUpdater Service
linuxPrevent HTTP parsing by disabling the vulnerable service if not needed.
🧯 If You Can't Patch
- Segment cameras on isolated VLAN with strict firewall rules.
- Monitor network traffic for unusual HTTP patterns to/from cameras.
🔍 How to Verify
Check if Vulnerable:
Check firmware version in camera web interface under System > Information.Check Version:
Not applicable - use web interface.Verify Fix Applied:
Verify firmware version is updated beyond 5.0.082.1.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP response parsing errors in camera logs
- AgentUpdater service crashes
Network Indicators:
- Malformed HTTP responses sent to camera on port 80/443
- Unexpected outbound connections from camera
SIEM Query:
source="camera_logs" AND ("heap overflow" OR "AgentUpdater crash")