CVE-2019-14562

What it actually does

Integer overflow in DxeImageVerificationHandler() within EDK II firmware allows local authenticated users to trigger a denial of service condition during image verification.

Why it matters to the business

Systems using affected firmware or Linux distributions may experience unexpected crashes or boot failures, leading to operational downtime and potential loss of availability for servers or devices relying on this UEFI implementation.

How an attack unfolds

An authenticated local attacker supplies a specially crafted image or binary that is processed by the vulnerable verification handler, causing the integer overflow to manifest as a crash or hang without requiring elevated privileges or network access.

How to fix it

Upgrade Tianocore EDK2 to a patched release that resolves the integer overflow in the verification handler; for Debian Linux, apply available distribution security updates that incorporate the upstream fix. Where immediate patching is not feasible, restrict local user access and monitor for anomalous boot behavior.

How to confirm the fix worked

Confirm exposure by reviewing firmware or package versions against known vulnerable EDK II releases; after remediation, retest image verification paths with boundary-case inputs and verify absence of crashes in DxeImageVerificationHandler.

Typical attack path

1. Obtain local authenticated access to a system running affected EDK II-based firmware
2. Prepare and supply a malicious image or executable crafted to trigger the overflow in DxeImageVerificationHandler
3. Trigger image verification during boot, load, or runtime operation
4. Observe resulting denial of service through system crash or unresponsiveness

How to detect it

Review system and firmware logs for crashes or errors originating from DxeImageVerificationHandler during boot or image load operations; look for repeated local authentication events followed by service unavailability on affected platforms.

What your security team should do

• Prioritize patching EDK II firmware on all affected devices given the 2144-day window since disclosure
• Audit local access controls to limit authenticated users who could trigger the flaw
• Incorporate firmware and bootloader integrity checks into regular vulnerability scanning
• Monitor upstream Tianocore and Debian advisories for any retroactive fixed versions