Evervault Go SDK: Incomplete PCR Validation in Enclave Attestation for non-Evervault hosted Enclaves
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 1.3.2
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: no
- Technical impact: total
Summary
Evervault is a payment security solution. A vulnerability was identified in the `evervault-go` SDK’s attestation verification logic in versions of `evervault-go` prior to 1.3.2 that may allow incomplete documents to pass validation. This may cause the client to trust an enclave operator that does not meet expected integrity guarantees. The exploitability of this issue is limited in Evervault-hosted environments as an attacker would require the pre-requisite ability to serve requests from specific evervault domain names, following from our ACME challenge based TLS certificate acquisition pipeline. The vulnerability primarily affects applications which only check PCR8. Though the efficacy is also reduced for applications that check all PCR values, the impact is largely remediated by checking PCR 0, 1 and 2. The identified issue has been addressed in version 1.3.2 by validating attestation documents before storing in the cache, and replacing the naive equality checks with a new SatisfiedBy check. Those who useevervault-go to attest Enclaves that are hosted outside of Evervault environments and cannot upgrade have two possible workarounds available. Modify the application logic to fail verification if PCR8 is not explicitly present and non-empty and/or add custom pre-validation to reject documents that omit any required PCRs.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- evervault evervault-go
fixed in 1.3.2
- github.com/evervault/evervault-goGo
fixed in 1.3.2