CVE-2021-26607
📋 TL;DR
CVE-2021-26607 is an improper input validation vulnerability in the execDefaultBrowser method of NEXACRO17 that allows remote attackers to execute arbitrary commands on affected systems. This affects organizations using vulnerable versions of NEXACRO17 software, potentially leading to complete system compromise.
💻 Affected Systems
- NEXACRO17
📦 What is this software?
Nexacro by Tobesoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with administrative privileges, data exfiltration, ransomware deployment, and lateral movement across the network.
Likely Case
Remote code execution leading to malware installation, credential theft, and establishment of persistent backdoors.
If Mitigated
Limited impact with proper network segmentation, application whitelisting, and least privilege principles in place.
🎯 Exploit Status
Improper input validation vulnerabilities typically have low exploitation complexity once the attack vector is identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not explicitly stated in provided references
Vendor Advisory: https://www.boho.or.kr/krcert/secNoticeView.do?bulletin_writing_sequence=36289
Restart Required: Yes
Instructions:
1. Contact NEXACRO vendor for patch information 2. Apply the latest security update 3. Restart affected systems 4. Verify patch installation
🔧 Temporary Workarounds
Network Segmentation
allIsolate systems running NEXACRO17 from critical networks and internet access
Application Control
windowsImplement application whitelisting to prevent unauthorized command execution
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable systems
- Deploy endpoint detection and response (EDR) solutions with behavioral monitoring
🔍 How to Verify
Check if Vulnerable:
Check NEXACRO17 version against vendor advisory and verify if execDefaultBrowser method exists in applicationCheck Version:
Check application properties or vendor documentation for version informationVerify Fix Applied:
Verify patch installation through vendor-provided verification method and test execDefaultBrowser functionality📡 Detection & Monitoring
Log Indicators:
- Unusual process execution from NEXACRO17
- Suspicious command-line arguments in process creation events
- Failed execution attempts in application logs
Network Indicators:
- Unexpected outbound connections from NEXACRO17 processes
- Command and control traffic patterns
SIEM Query:
Process Creation where (Image contains 'nexacro' OR ParentImage contains 'nexacro') AND (CommandLine contains suspicious patterns)