CVE-2024-6285 – An integer underflow vulnerability in Renesas A... (How to Fix)

Q: What is the severity of CVE-2024-6285?

CVE-2024-6285 has a CVSS score of 7.5 (HIGH). An integer underflow vulnerability in Renesas ARM Trusted Firmware's image range check calculations could allow attackers to bypass address restrictions and load images to unauthorized memory locations. This affects systems using vulnerable versions of Renesas's ARM Trusted Firmware implementation. The vulnerability could potentially lead to arbitrary code execution or system compromise.

📋 TL;DR

An integer underflow vulnerability in Renesas ARM Trusted Firmware's image range check calculations could allow attackers to bypass address restrictions and load images to unauthorized memory locations. This affects systems using vulnerable versions of Renesas's ARM Trusted Firmware implementation. The vulnerability could potentially lead to arbitrary code execution or system compromise.

💻 Affected Systems

Products:

Renesas ARM Trusted Firmware implementation

Versions: Versions prior to commit b596f580637bae919b0ac3a5471422a1f756db3b

Operating Systems: Any OS running on affected Renesas hardware with vulnerable firmware

Default Config Vulnerable: ⚠️ Yes

Notes: Affects Renesas R-Car platform devices using ARM Trusted Firmware. Requires firmware update capability to exploit.

📦 What is this software?

Rcar Gen3 by Renesas

View all CVEs affecting Rcar Gen3 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system compromise through arbitrary code execution at privileged firmware level, potentially bypassing secure boot protections.

🟠

Likely Case

Privilege escalation or firmware-level code execution allowing attackers to bypass security controls and gain persistent access.

🟢

If Mitigated

Limited impact if proper firmware validation and secure boot are enforced, though still a serious firmware-level vulnerability.

🌐 Internet-Facing: LOW (Firmware vulnerabilities typically require local access or supply chain compromise)

🏢 Internal Only: MEDIUM (Requires local access or administrative privileges to exploit)

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires firmware update capabilities or administrative access. No public exploit code available at this time.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Commit b596f580637bae919b0ac3a5471422a1f756db3b or later

Vendor Advisory: https://asrg.io/security-advisories/cve-2024-6285/

Restart Required: Yes

Instructions:

1. Update ARM Trusted Firmware to commit b596f580637bae919b0ac3a5471422a1f756db3b or later. 2. Rebuild firmware image. 3. Flash updated firmware to affected devices. 4. Verify secure boot chain integrity.

🔧 Temporary Workarounds

Restrict firmware update capabilities

all

Limit who can perform firmware updates and require multi-factor authentication for firmware modification operations.

Enable secure boot verification

all

Ensure secure boot is properly configured to verify firmware integrity before execution.

🧯 If You Can't Patch

Implement strict access controls to prevent unauthorized firmware updates
Monitor for firmware modification attempts and maintain firmware integrity checks

🔍 How to Verify

Check if Vulnerable:

Check ARM Trusted Firmware version against commit hash b596f580637bae919b0ac3a5471422a1f756db3b. If using earlier version, system is vulnerable.

Check Version:

Check firmware version through device-specific methods (varies by Renesas platform)

Verify Fix Applied:

Verify firmware version includes commit b596f580637bae919b0ac3a5471422a1f756db3b and secure boot verification passes.

📡 Detection & Monitoring

Log Indicators:

Unexpected firmware update attempts
Secure boot failures
Firmware integrity check failures

Network Indicators:

Unauthorized firmware update traffic
Unexpected connections to firmware update servers

SIEM Query:

source="firmware_logs" AND (event_type="update_attempt" OR event_type="integrity_failure")

📊 Metadata

CVE ID: CVE-2024-6285

CVSS v3 Score: 7.5 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

CWE: CWE-191

Published: June 24, 2024

Last Updated: November 21, 2024

🔗 References

https://asrg.io/security-advisories/cve-2024-6285/ Third Party Advisory
https://github.com/renesas-rcar/arm-trusted-firmware/commit/b596f580637bae919b0ac3a5471422a1f756db3b Patch
https://asrg.io/security-advisories/cve-2024-6285/ Third Party Advisory
https://github.com/renesas-rcar/arm-trusted-firmware/commit/b596f580637bae919b0ac3a5471422a1f756db3b Patch

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