CVE-2016-9684
📋 TL;DR
This CVE allows remote attackers to execute arbitrary commands on SonicWall Secure Remote Access servers through the web administrative interface. Attackers can inject malicious commands via the 'CERT' parameter in the viewcert CGI component, gaining shell access as the 'nobody' user. Organizations running vulnerable SonicWall SMA 100 series appliances with internet-facing administrative interfaces are at risk.
💻 Affected Systems
- SonicWall Secure Mobile Access (SMA) 100 series
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to pivot to internal networks, install persistent backdoors, exfiltrate sensitive data, and use the compromised system as a launch point for further attacks.
Likely Case
Remote command execution leading to unauthorized access, potential data theft, and system manipulation. Attackers would have limited privileges as the 'nobody' user but could escalate privileges.
If Mitigated
Minimal impact if the administrative interface is not internet-facing, proper network segmentation is in place, and intrusion detection systems are monitoring for suspicious activity.
🎯 Exploit Status
Exploit code is publicly available on Pastebin and other sources. The vulnerability requires no authentication and has simple exploitation steps.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 8.1.0.7 and later
Vendor Advisory: https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2016-0005
Restart Required: Yes
Instructions:
1. Download SonicWall SMA 100 series firmware version 8.1.0.7 or later from the SonicWall support portal. 2. Backup current configuration. 3. Upload and install the new firmware via the administrative interface. 4. Reboot the appliance after installation completes.
🔧 Temporary Workarounds
Disable web administrative interface
allTemporarily disable the web administrative interface to prevent exploitation while planning for patching
Restrict access to administrative interface
allImplement firewall rules to restrict access to the administrative interface to trusted IP addresses only
🧯 If You Can't Patch
- Implement strict network access controls to limit who can reach the administrative interface
- Deploy a web application firewall (WAF) with command injection protection rules
🔍 How to Verify
Check if Vulnerable:
Check if the /cgi-bin/viewcert endpoint exists and responds. Test with a harmless command injection payload like 'CERT=test;id' to see if command execution occurs.Check Version:
Check the firmware version in the SonicWall SMA administrative interface under System > Status or via SSH if enabledVerify Fix Applied:
Verify firmware version is 8.1.0.7 or later. Test the same command injection payload to confirm it no longer executes commands.📡 Detection & Monitoring
Log Indicators:
- Unusual commands in web server logs containing the 'CERT' parameter
- Suspicious system commands executed by the 'nobody' user
- Multiple failed exploitation attempts to /cgi-bin/viewcert
Network Indicators:
- Unusual outbound connections from the SonicWall appliance
- Traffic patterns indicating command and control communication
- HTTP requests to /cgi-bin/viewcert with shell metacharacters in parameters
SIEM Query:
source="sonicwall-logs" AND (uri="/cgi-bin/viewcert" AND (param="CERT" CONTAINS ";" OR param="CERT" CONTAINS "|" OR param="CERT" CONTAINS "`"))🔗 References
- http://documents.software.dell.com/sonicwall-sma-100-series/8.1.0.7/release-notes/resolved-issues?ParentProduct=868
- http://pastebin.com/g1e2qU6N
- http://www.securityfocus.com/bid/96375
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2016-0005
- http://documents.software.dell.com/sonicwall-sma-100-series/8.1.0.7/release-notes/resolved-issues?ParentProduct=868
- http://pastebin.com/g1e2qU6N
- http://www.securityfocus.com/bid/96375
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2016-0005
