CVE-2021-20028
📋 TL;DR
This CVE describes a critical SQL injection vulnerability in SonicWall Secure Remote Access (SRA) appliances. Attackers can exploit this to execute arbitrary SQL commands, potentially leading to data theft, authentication bypass, or complete system compromise. Only affects end-of-life SRA products running specific firmware versions.
💻 Affected Systems
- SonicWall Secure Remote Access (SRA) appliances
📦 What is this software?
Sra Va Firmware by Sonicwall
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the SRA appliance allowing attackers to steal all stored credentials, pivot to internal networks, install persistent backdoors, and potentially compromise connected systems.
Likely Case
Authentication bypass leading to unauthorized access to VPN connections and internal network resources, followed by data exfiltration or lateral movement.
If Mitigated
Limited impact with proper network segmentation, strong authentication controls, and monitoring that detects SQL injection attempts before successful exploitation.
🎯 Exploit Status
This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0017
Restart Required: No
Instructions:
No official patch available as products are end-of-life. SonicWall recommends immediate migration to supported products.
🔧 Temporary Workarounds
Network Segmentation and Access Control
allRestrict network access to SRA appliances using firewall rules to only allow connections from trusted IP addresses.
Web Application Firewall (WAF)
allDeploy a WAF in front of SRA appliances with SQL injection detection and blocking rules enabled.
🧯 If You Can't Patch
- Immediately isolate affected SRA appliances from the internet and internal networks
- Begin migration to supported SonicWall SMA or other modern remote access solutions
🔍 How to Verify
Check if Vulnerable:
Check firmware version via SRA web admin interface or SSH: show versionCheck Version:
show versionVerify Fix Applied:
Verify migration to supported product is complete and old SRA appliances are decommissioned📡 Detection & Monitoring
Log Indicators:
- Unusual SQL query patterns in application logs
- Multiple failed login attempts followed by successful access
- Administrative actions from unexpected IP addresses
Network Indicators:
- SQL injection patterns in HTTP requests to SRA appliances
- Unexpected outbound connections from SRA appliances
SIEM Query:
source="sra_logs" AND ("sql" OR "union" OR "select" OR "insert" OR "update" OR "delete")