Authentication bypass and disclosure via Base64 over-read
Published Aug 23, 2023 · Updated Oct 3, 2024
Out-of-bounds access in Varnish Software Varnish Digest Module before 1.0.3 allows remote attackers to bypass authentication. The digest.base64_decode, digest.base64url_decode, and digest.base64url_nopad_decode functions perform out-of-bounds workspace reads while decoding crafted input. Exploitation requires the module to be loaded and an affected function to be used in VCL; the configuration determines whether authentication is bypassed or workspace data is disclosed.
Summary
What happened
Out-of-bounds access in Varnish Software Varnish Digest Module before 1.0.3 allows remote attackers to bypass authentication. The digest.base64_decode, digest.base64url_decode, and digest.base64url_nopad_decode functions perform out-of-bounds workspace reads while decoding crafted input. Exploitation requires the module to be loaded and an affected function to be used in VCL; the configuration determines whether authentication is bypassed or workspace data is disclosed.
The record
- CVE
- CVE-2023-41104
- Published
- Aug 23, 2023
- Updated
- Oct 3, 2024
- Vendor
- Varnish Software
- Product
- Varnish Digest Module
- Classifications
- CWE-119, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 23, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <1.0.3
- Affected versionversion=varnish_enterprise_6.0x <6.0.11r5
What conditions does exploitation require?
What is affected?
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
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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