CVE-2021-26612
📋 TL;DR
CVE-2021-26612 is an improper input validation vulnerability in Nexacro platform's copy method that allows remote attackers to create arbitrary files containing malicious code, potentially leading to arbitrary command execution. This affects organizations using vulnerable versions of Nexacro platform. Attackers can exploit this without authentication to compromise affected systems.
💻 Affected Systems
- Nexacro platform
📦 What is this software?
Nexacro by Tobesoft
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with remote code execution, data exfiltration, and lateral movement within the network.
Likely Case
Arbitrary file creation leading to command execution, potentially resulting in malware deployment or system takeover.
If Mitigated
Limited impact with proper network segmentation and input validation controls in place.
🎯 Exploit Status
The vulnerability description suggests straightforward exploitation via the copy method without authentication requirements.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in provided references, but vendor likely released patched version.
Vendor Advisory: https://www.boho.or.kr/krcert/secNoticeView.do?bulletin_writing_sequence=36380
Restart Required: Yes
Instructions:
1. Contact Nexacro vendor for latest patched version. 2. Apply vendor-provided patch. 3. Restart affected Nexacro services. 4. Verify patch application.
🔧 Temporary Workarounds
Disable copy method
allTemporarily disable or restrict access to the vulnerable copy method in Nexacro configuration.
Specific commands depend on Nexacro configuration; consult vendor documentation.
Network segmentation
allIsolate Nexacro systems from untrusted networks and implement strict firewall rules.
Configure firewall to restrict inbound access to Nexacro ports from trusted sources only.
🧯 If You Can't Patch
- Implement strict input validation and sanitization for all copy method inputs.
- Deploy web application firewall (WAF) with rules to detect and block malicious copy method requests.
🔍 How to Verify
Check if Vulnerable:
Check Nexacro version against vendor advisory; test if copy method accepts malicious input leading to arbitrary file creation.Check Version:
Check Nexacro administration interface or configuration files for version information.Verify Fix Applied:
Verify patched version is installed and test that copy method properly validates input and prevents arbitrary file creation.📡 Detection & Monitoring
Log Indicators:
- Unusual file creation events via copy method
- Suspicious command execution following file creation
Network Indicators:
- Unexpected network connections from Nexacro systems
- Anomalous traffic patterns to/from Nexacro ports
SIEM Query:
Example: 'source="nexacro" AND (event="file_create" OR event="command_exec")'