Secret inference via compiler-optimized digest comparison
Published Aug 22, 2023 · Updated Oct 3, 2024
Timing side channel in Python hmac.compare_digest through 3.9.1 allows remote attackers to infer secret comparison data. Volatile input pointers force reads but do not force every XOR result into the accumulator, so compiler optimization can make runtime vary with the first unequal byte. Exploitation requires repeated, precise timing observations of a consuming application's digest comparisons; disclosure is limited to information inferred from timing.
Summary
What happened
Timing side channel in Python hmac.compare_digest through 3.9.1 allows remote attackers to infer secret comparison data. Volatile input pointers force reads but do not force every XOR result into the accumulator, so compiler optimization can make runtime vary with the first unequal byte. Exploitation requires repeated, precise timing observations of a consuming application's digest comparisons; disclosure is limited to information inferred from timing.
The record
- CVE
- CVE-2022-48566
- Published
- Aug 22, 2023
- Updated
- Oct 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-362
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 22, 2023CVE publishedPublication date reported by the CVE source.
- Oct 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
- hmac.compare_digest compiler-optimization timing demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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