CVE-2025-27027
📋 TL;DR
This vulnerability allows users with vpuser credentials to bypass restricted shell (rbash) limitations and gain a full-featured Linux shell on affected devices. Attackers with valid vpuser credentials can escalate privileges beyond intended restrictions. This affects systems using rbash to restrict vpuser SSH access.
💻 Affected Systems
- Specific product information not provided in CVE description
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attacker gains full shell access, potentially leading to privilege escalation, data exfiltration, or complete system compromise.
Likely Case
Authorized but restricted users bypass intended limitations, gaining unauthorized system access and potentially modifying configurations.
If Mitigated
Users remain confined to rbash restrictions with only allowed commands available.
🎯 Exploit Status
Requires valid vpuser credentials and SSH access. Exploitation likely involves specific command sequences to escape rbash.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified
Vendor Advisory: https://www.cvcn.gov.it/cvcn/cve/CVE-2025-27027
Restart Required: No
Instructions:
1. Monitor vendor for patches. 2. Apply vendor-recommended updates when available. 3. Verify rbash restrictions are properly enforced after patching.
🔧 Temporary Workarounds
Strengthen rbash configuration
linuxImplement stricter rbash restrictions and command whitelisting
Review /etc/passwd for vpuser shell settings
Audit ~vpuser/.bashrc and ~vpuser/.profile
Implement command whitelist in restricted shell configuration
SSH access controls
linuxRestrict SSH access and implement additional authentication controls
Configure sshd_config with 'AllowUsers' restrictions
Implement two-factor authentication for vpuser accounts
Set up IP-based access controls
🧯 If You Can't Patch
- Monitor vpuser SSH sessions for unusual activity and command execution
- Implement network segmentation to isolate affected systems from critical resources
🔍 How to Verify
Check if Vulnerable:
Test vpuser SSH access and attempt to execute restricted commands or escape rbash using known techniques.Check Version:
Check system documentation or vendor information for specific version details.Verify Fix Applied:
Verify vpuser SSH sessions are properly restricted to allowed commands only and cannot obtain full shell.📡 Detection & Monitoring
Log Indicators:
- SSH logins with vpuser account followed by unusual command execution
- Failed rbash restriction attempts in system logs
- Commands typically blocked by rbash being executed
Network Indicators:
- SSH connections to vpuser accounts from unusual sources
- Increased SSH session activity from vpuser accounts
SIEM Query:
source="sshd" AND user="vpuser" AND (event="session opened" OR event="command executed") | stats count by src_ip, command