CVE-2024-53085

What it actually does

Race condition in TPM handling where TPM_CHIP_FLAG_SUSPENDED is set at the end of tpm_pm_suspend allowing tpm_hwrng_read to execute concurrently while suspend operations are in progress.

Why it matters to the business

Systems using TPM for random number generation or security functions may experience inconsistent behavior during power state transitions on older Ubuntu releases; low immediate risk given static EPSS and lack of KEV listing despite 692 days of public availability.

How an attack unfolds

An attacker with local execution capability times a concurrent tpm_hwrng_read call against an in-progress tpm_pm_suspend on an affected kernel to exploit the window before the suspended flag is asserted; listed threat actor references to espionage and financial campaigns do not indicate confirmed use against this specific flaw.

How to fix it

Upgrade flashplugin-nonfree on Ubuntu 14.04 LTS to version 11.2.202.559ubuntu0.14.04.1; apply corresponding Linux kernel patches that lock the TPM chip before flag checks in both tpm_pm_suspend and tpm_hwrng_read.

How to confirm the fix worked

Confirm package version matches or exceeds the listed fixed release; review kernel source for the moved TPM_CHIP_FLAG_SUSPENDED check inside tpm_get_random under lock acquisition.

Typical attack path

1. Obtain local code execution on target system
2. Trigger system suspend while monitoring TPM state
3. Invoke tpm_hwrng_read during the unprotected window
4. Observe or influence TPM operation outcome

How to detect it

Review system suspend logs and TPM driver traces for concurrent access attempts around suspend events; examine kernel ring buffer entries referencing tpm_pm_suspend and tpm_hwrng_read ordering anomalies.

What your security team should do

• Prioritize patching affected Ubuntu 14.04 systems within standard maintenance windows
• Monitor EPSS trend for any increase above 0.002
• Audit TPM-dependent services for suspend/resume reliability after update