CVE-2021-27258
📋 TL;DR
This vulnerability allows unauthenticated remote attackers to escalate privileges from Guest to Administrator on SolarWinds Orion Platform installations. The flaw exists in the SaveUserSetting endpoint which lacks proper access controls. All organizations running affected SolarWinds Orion Platform versions are at risk.
💻 Affected Systems
- SolarWinds Orion Platform
📦 What is this software?
Orion Platform by Solarwinds
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with administrative control over the SolarWinds Orion Platform, enabling further network reconnaissance, lateral movement, and persistence.
Likely Case
Unauthenticated attackers gain administrative access to the SolarWinds management platform, allowing them to modify configurations, deploy malicious updates, or access sensitive monitoring data.
If Mitigated
With proper network segmentation and access controls, impact is limited to the SolarWinds Orion system itself, though administrative control still poses significant risk.
🎯 Exploit Status
The vulnerability was actively exploited in the wild as part of the SolarWinds supply chain attack. Exploitation requires no authentication and minimal technical skill.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2020.2.1 HF 2 and later
Vendor Advisory: https://www.solarwinds.com/securityadvisory
Restart Required: Yes
Instructions:
1. Download the latest hotfix from the SolarWinds Customer Portal. 2. Stop all Orion services. 3. Apply the hotfix. 4. Restart Orion services. 5. Verify the patch is applied successfully.
🔧 Temporary Workarounds
Network Access Restriction
allRestrict network access to the SolarWinds Orion Platform to only trusted administrative networks
Use firewall rules to block external access to Orion Platform ports (typically 17778, 17779)
Endpoint Disablement
windowsDisable the vulnerable SaveUserSetting endpoint if not required
Modify web.config to restrict access to the vulnerable endpoint
🧯 If You Can't Patch
- Immediately isolate the SolarWinds Orion server from the internet and restrict internal access
- Implement strict network segmentation and monitor all traffic to/from the Orion server
🔍 How to Verify
Check if Vulnerable:
Check Orion Platform version in the web interface under Settings > All Settings > About OrionCheck Version:
Check via Orion web interface or examine installed programs in Windows Control PanelVerify Fix Applied:
Verify version is 2020.2.1 HF 2 or later and test that unauthenticated access to SaveUserSetting endpoint is blocked📡 Detection & Monitoring
Log Indicators:
- Unauthenticated POST requests to /Orion/.../SaveUserSetting.aspx
- User privilege escalation events in Orion audit logs
- Guest users being granted administrative permissions
Network Indicators:
- Unusual outbound connections from Orion server
- Traffic to SaveUserSetting endpoint from unauthenticated sources
SIEM Query:
source="Orion" AND (uri="*SaveUserSetting*" OR event="privilege escalation")