Denial of service via quadratic password hashing
Published Feb 19, 2022 · Updated Aug 6, 2024
Denial of service in sha256crypt and sha512crypt through 0.6 allows attackers to consume excessive CPU via crafted long passwords. The hashing algorithm performs work proportional to the square of password length, so processing an unusually long password monopolizes compute. The network, unauthenticated reachability described by CVSS applies only when an exposed service accepts attacker-controlled passwords; the bounded consequence is service slowdown or interruption rather than data disclosure or modification.
Summary
What happened
Denial of service in sha256crypt and sha512crypt through 0.6 allows attackers to consume excessive CPU via crafted long passwords. The hashing algorithm performs work proportional to the square of password length, so processing an unusually long password monopolizes compute. The network, unauthenticated reachability described by CVSS applies only when an exposed service accepts attacker-controlled passwords; the bounded consequence is service slowdown or interruption rather than data disclosure or modification.
The record
- CVE
- CVE-2016-20013
- Published
- Feb 19, 2022
- Updated
- Aug 6, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-770, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 19, 2022CVE 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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What is affected?
Affected products and versions are unavailable in this record.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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