CVE-2023-43635 — eve
HIGHCVE-2023-43635 is a high-severity (CVSS 8.8) CWE-328 vulnerability in github.com/lf-edge/eve. A fix is available for github.com/lf-edge/eve — see the affected versions and patch details below.
Vault Key Sealed With SHA1 PCRs
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-43635.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/lf-edge/eveReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Vault Key Sealed With SHA1 PCRs
The measured boot solution implemented in EVE OS leans on a PCR locking mechanism.
Different parts of the system update different PCR values in the TPM, resulting in a unique value for each PCR entry.
These PCRs are then used in order to seal/unseal a key from the TPM which is used to encrypt/decrypt the “vault” directory.
This “vault” directory is the most sensitive point in the system and as such, its content should be protected.
This mechanism is noted in Zededa’s documentation as the “measured boot” mechanism, designed to protect said “vault”.
The code that’s responsible for generating and fetching the key from the TPM assumes that SHA256 PCRs are used in order to seal/unseal the key, and as such their presence is being checked.
The issue here is that the key is not sealed using SHA256 PCRs, but using SHA1 PCRs. This leads to several issues:
• Machines that have their SHA256 PCRs enabled but SHA1 PCRs disabled, as well as not sealing their keys at all, meaning the “vault” is not protected from an attacker.
• SHA1 is considered insecure and reduces the complexity level required to unseal the key in machines which have their SHA1 PCRs enabled.
An attacker can very easily retrieve the contents of the “vault”, which will effectively render the “measured boot” mechanism meaningless.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/lf-edge/eve | all versions | 0.0.0-20230519072751-977f42b07fa9go get github.com/lf-edge/eve@v0.0.0-20230519072751-977f42b07fa9 |
Affected Products
edge virtualization enginelinuxfoundationDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lf-edge/eve, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/lf-edge/eve to 0.0.0-20230519072751-977f42b07fa9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-43635 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2023-43635 in your dependencies?
Find it across Go, including transitive dependencies.