Authentication bypass via nonconstant-time credential comparison
Published Jan 22, 2024 · Updated May 30, 2025
Observable timing differences in darkhttpd before 1.15 allow remote attackers to recover HTTP Basic authentication credentials. The request authentication path compares the client-supplied Authorization value with the configured --auth secret using strcmp, which returns after the first mismatch and exposes matching-prefix length through response timing. Exploitation requires Basic authentication to be enabled and repeated network measurements, and recovered credentials grant access to protected static content.
Summary
What happened
Observable timing differences in darkhttpd before 1.15 allow remote attackers to recover HTTP Basic authentication credentials. The request authentication path compares the client-supplied Authorization value with the configured --auth secret using strcmp, which returns after the first mismatch and exposes matching-prefix length through response timing. Exploitation requires Basic authentication to be enabled and repeated network measurements, and recovered credentials grant access to protected static content.
The record
- CVE
- CVE-2024-23771
- Published
- Jan 22, 2024
- Updated
- May 30, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-203, T1110.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 22, 2024CVE publishedPublication date reported by the CVE source.
- May 30, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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.
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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