CVE-2023-39535
📋 TL;DR
This CVE describes an improper input validation vulnerability in AMI AptioV BIOS that allows attackers on the local network to exploit the system. Successful exploitation could lead to loss of confidentiality, integrity, and availability of the affected system. This affects systems using vulnerable versions of AMI AptioV BIOS firmware.
💻 Affected Systems
- AMI AptioV BIOS
📦 What is this software?
⚠️ 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
Complete system compromise allowing attacker to execute arbitrary code at BIOS level, potentially persisting across OS reinstalls and enabling data theft, system destruction, or establishing persistent foothold.
Likely Case
Attacker gains elevated privileges or executes code in BIOS context, potentially bypassing OS-level security controls and compromising system integrity.
If Mitigated
With proper network segmentation and BIOS-level protections, exploitation attempts are blocked or detected before causing damage.
🎯 Exploit Status
Exploitation requires local network access and knowledge of the vulnerability. No public proof-of-concept has been identified.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Consult system manufacturer for specific BIOS update version
Vendor Advisory: https://9443417.fs1.hubspotusercontent-na1.net/hubfs/9443417/Security%20Advisories/AMI-SA-2023008.pdf
Restart Required: Yes
Instructions:
1. Identify system manufacturer and model. 2. Check manufacturer's support site for BIOS/UEFI firmware updates. 3. Download appropriate BIOS update for your system. 4. Follow manufacturer's instructions to flash BIOS. 5. Restart system to apply update.
🔧 Temporary Workarounds
Network Segmentation
allIsolate systems with vulnerable BIOS from untrusted networks and limit local network access.
BIOS Security Settings
allEnable BIOS-level security features like secure boot and BIOS password protection.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate vulnerable systems
- Monitor network traffic for suspicious BIOS/UEFI-related network activity
🔍 How to Verify
Check if Vulnerable:
Check BIOS version in system settings (F2/DEL during boot) or use manufacturer's system information tools. Compare against vendor's patched versions list.Check Version:
Windows: wmic bios get smbiosbiosversion
Linux: dmidecode -s bios-versionVerify Fix Applied:
Verify BIOS version after update matches manufacturer's recommended patched version. Check that BIOS update was successful in system logs.📡 Detection & Monitoring
Log Indicators:
- BIOS/UEFI update logs showing unauthorized changes
- System logs showing unexpected BIOS-level activity
Network Indicators:
- Unusual network traffic to/from BIOS management interfaces
- Suspicious local network traffic targeting BIOS services
SIEM Query:
Search for BIOS/UEFI update events outside of maintenance windows or from unauthorized sources