HMAC disclosure via non-constant signature comparison
Published Dec 27, 2022 · Updated Apr 11, 2025
Timing side channel in John Rowley jwt before 0.0.0-20170426191122-ca1404ee6e83 allows remote attackers to determine an expected HMAC. Algorithm.validateSignature Base64-encodes its computed signature and uses strings.Compare against the token signature, returning sooner at the first mismatching byte instead of comparing in constant time. Exploitation requires many validation requests over a low-latency connection; the reported consequence is disclosure of a valid HMAC, with no reported integrity or availability impact.
Summary
What happened
Timing side channel in John Rowley jwt before 0.0.0-20170426191122-ca1404ee6e83 allows remote attackers to determine an expected HMAC. Algorithm.validateSignature Base64-encodes its computed signature and uses strings.Compare against the token signature, returning sooner at the first mismatching byte instead of comparing in constant time. Exploitation requires many validation requests over a low-latency connection; the reported consequence is disclosure of a valid HMAC, with no reported integrity or availability impact.
The record
- CVE
- CVE-2015-10004
- Published
- Dec 27, 2022
- Updated
- Apr 11, 2025
- Vendor
- John Rowley
- Product
- jwt
- Classifications
- CWE-668
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 27, 2022CVE publishedPublication date reported by the CVE source.
- Apr 11, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <0.0.0-20170426191122-ca1404ee6e83
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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