CVE-2021-43359
📋 TL;DR
Sunnet eHRD has a broken access control vulnerability that allows authenticated general users to access the account management page and escalate privileges. This enables remote attackers to execute arbitrary code, potentially taking full control of affected systems. Organizations using Sunnet eHRD software are affected.
💻 Affected Systems
- Sunnet eHRD
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attacker to execute arbitrary code, steal sensitive HR data, deploy ransomware, or disrupt business operations.
Likely Case
Privilege escalation leading to unauthorized access to sensitive HR data, user account manipulation, and potential lateral movement within the network.
If Mitigated
Limited impact with proper network segmentation and monitoring, potentially only affecting the eHRD application itself.
🎯 Exploit Status
Requires authenticated access but exploitation is straightforward once authenticated
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in references
Vendor Advisory: https://www.twcert.org.tw/tw/cp-132-5354-0aac0-1.html
Restart Required: Yes
Instructions:
1. Contact Sunnet for patch information
2. Apply the latest security update
3. Restart the eHRD service
4. Verify the fix
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to eHRD system to only authorized users and networks
Access Control Review
allReview and tighten user permissions to minimize attack surface
🧯 If You Can't Patch
- Implement strict network segmentation to isolate eHRD system
- Enforce principle of least privilege for all user accounts
- Implement application-level monitoring for suspicious activities
🔍 How to Verify
Check if Vulnerable:
Check if Sunnet eHRD is installed and accessible, then test authenticated access to account management pagesCheck Version:
Check eHRD administration panel or contact vendor for version informationVerify Fix Applied:
After patching, verify that authenticated general users cannot access account management functionality📡 Detection & Monitoring
Log Indicators:
- Unauthorized access attempts to account management pages
- Privilege escalation events
- Unusual user activity patterns
Network Indicators:
- Suspicious traffic to eHRD management interfaces
- Unexpected outbound connections from eHRD server
SIEM Query:
source="eHRD" AND (event="account_management_access" OR event="privilege_change")