CVE-2021-26625
📋 TL;DR
CVE-2021-26625 is an insufficient input validation vulnerability in Nexacro platform's automatic update function that allows remote attackers to download and execute arbitrary malicious files. This affects organizations using vulnerable versions of Nexacro platform software. Attackers can exploit this to gain unauthorized access and control over affected systems.
💻 Affected Systems
- Nexacro platform
📦 What is this software?
Nexacro by Tobesoft
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control, installing persistent backdoors, stealing sensitive data, and using the system as a pivot point for lateral movement within the network.
Likely Case
Initial foothold leading to ransomware deployment, data exfiltration, or installation of cryptocurrency miners on affected systems.
If Mitigated
Limited impact with proper network segmentation and endpoint protection blocking malicious file execution, though system integrity may still be compromised.
🎯 Exploit Status
The vulnerability requires no authentication and has straightforward exploitation path, making it attractive for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in provided references, but patches were released by vendor
Vendor Advisory: https://www.krcert.or.kr/krcert/secNoticeView.do?bulletin_writing_sequence=66661
Restart Required: Yes
Instructions:
1. Contact Nexacro vendor for latest security patches. 2. Apply patches to all affected Nexacro installations. 3. Restart services/systems as required. 4. Verify patch application.
🔧 Temporary Workarounds
Disable Automatic Updates
allTemporarily disable the automatic update function in Nexacro platform to prevent exploitation
Configuration specific to Nexacro platform - consult vendor documentation
Network Segmentation
allIsolate Nexacro systems from internet and restrict network access to trusted sources only
firewall rules to block inbound connections to Nexacro update ports
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Nexacro systems from untrusted networks
- Deploy application whitelisting to prevent execution of unauthorized files
🔍 How to Verify
Check if Vulnerable:
Check Nexacro platform version and configuration for automatic update functionality. Review system logs for unauthorized file download attempts.Check Version:
Nexacro-specific command or check through administration interfaceVerify Fix Applied:
Verify patch version from vendor and test update functionality with controlled inputs to ensure proper validation.📡 Detection & Monitoring
Log Indicators:
- Unexpected file downloads via update mechanism
- Execution of unfamiliar executable files
- Network connections to unusual external IPs from Nexacro process
Network Indicators:
- Outbound connections to suspicious domains/IPs from Nexacro systems
- Unusual file transfer patterns during update cycles
SIEM Query:
Process creation where parent process is Nexacro update service AND file hash not in approved list