Authentication bypass via shared static hash buffer
Published Jan 28, 2020 · Updated Aug 6, 2024
Authentication bypass in py-bcrypt before 0.3 allows remote attackers to gain account access through concurrent password checks. The hashing routine releases Python's global interpreter lock but writes each bcrypt result into a shared static buffer, allowing simultaneous calls to overwrite results before Python copies them. The hosting application must use the library for password verification and process overlapping requests; a replaced result can make an incorrect password check succeed.
Summary
What happened
Authentication bypass in py-bcrypt before 0.3 allows remote attackers to gain account access through concurrent password checks. The hashing routine releases Python's global interpreter lock but writes each bcrypt result into a shared static buffer, allowing simultaneous calls to overwrite results before Python copies them. The hosting application must use the library for password verification and process overlapping requests; a replaced result can make an incorrect password check succeed.
The record
- CVE
- CVE-2013-1895
- Published
- Jan 28, 2020
- Updated
- Aug 6, 2024
- Vendor
- py-bcrypt
- Product
- py-bcrypt
- Classifications
- CWE-307
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 28, 2020CVE publishedPublication date reported by the CVE source.
- Aug 6, 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?
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- Affected versionversion=before 0.3
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
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Technologies
Your stack
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Your stack
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