CVE-2021-44676
📋 TL;DR
CVE-2021-44676 is an authentication bypass vulnerability in Zoho ManageEngine Access Manager Plus that allows unauthenticated attackers to view sensitive data and modify application settings. This affects all versions before 4203. Organizations using this software for identity and access management are at risk.
💻 Affected Systems
- Zoho ManageEngine Access Manager Plus
📦 What is this software?
Manageengine Access Manager Plus by Zohocorp
Manageengine Access Manager Plus by Zohocorp
Manageengine Access Manager Plus by Zohocorp
Manageengine Access Manager Plus by Zohocorp
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the access management system, allowing attackers to modify access controls, view all protected data, and potentially pivot to other systems.
Likely Case
Unauthorized viewing of access control details and modification of application settings, potentially enabling privilege escalation or data exposure.
If Mitigated
Limited impact if proper network segmentation and monitoring are in place, but authentication bypass remains a critical finding.
🎯 Exploit Status
Authentication bypass vulnerabilities typically have low exploitation complexity and are often weaponized quickly.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4203 and later
Restart Required: Yes
Instructions:
1. Download Access Manager Plus build 4203 or later from ManageEngine website. 2. Backup current installation. 3. Stop the Access Manager Plus service. 4. Install the update. 5. Restart the service.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to Access Manager Plus to only trusted IP addresses and networks.
Web Application Firewall
allDeploy WAF rules to block suspicious authentication bypass attempts.
🧯 If You Can't Patch
- Isolate the Access Manager Plus instance from internet access and restrict internal access to only necessary users.
- Implement additional authentication layers and monitor for unusual access patterns or configuration changes.
🔍 How to Verify
Check if Vulnerable:
Check the Access Manager Plus version in the web interface under Help > About or via the server console.Check Version:
On Windows: Check program version in Control Panel. On Linux: Check installation directory for version files or use web interface.Verify Fix Applied:
Verify the version is 4203 or later and test authentication requirements for previously vulnerable endpoints.📡 Detection & Monitoring
Log Indicators:
- Unauthenticated access to sensitive endpoints
- Configuration changes from unauthenticated users
- Failed authentication attempts followed by successful access
Network Indicators:
- HTTP requests to sensitive endpoints without authentication headers
- Unusual traffic patterns to access management endpoints
SIEM Query:
source="access_manager_plus" AND (status=200 AND auth="none") OR (endpoint CONTAINS "/api/" AND auth="none")🔗 References
- https://pitstop.manageengine.com/portal/en/community/topic/security-advisory-authentication-bypass-vulnerability-in-access-manager-plus-build-4202-and-prior
- https://www.manageengine.com
- https://pitstop.manageengine.com/portal/en/community/topic/security-advisory-authentication-bypass-vulnerability-in-access-manager-plus-build-4202-and-prior
- https://www.manageengine.com
