Cryptographic secret leakage via compiler-induced GHASH branching
Published Oct 23, 2024 · Updated Oct 24, 2024
Timing side channel in Botan before 3.6.0 allows remote attackers to infer AES-GCM secrets through repeated timing observations. In GHASH key_schedule, compiler optimization converts the multiplication of a secret-dependent low bit by the reduction constant into a conditional branch instead of constant-time masking. Exposure requires an affected build, observed with Clang 15 on RISC-V, and a consuming application that makes repeated AES-GCM operations and their timing remotely observable.
Summary
What happened
Timing side channel in Botan before 3.6.0 allows remote attackers to infer AES-GCM secrets through repeated timing observations. In GHASH key_schedule, compiler optimization converts the multiplication of a secret-dependent low bit by the reduction constant into a conditional branch instead of constant-time masking. Exposure requires an affected build, observed with Clang 15 on RISC-V, and a consuming application that makes repeated AES-GCM operations and their timing remotely observable.
The record
- CVE
- CVE-2024-50382
- Published
- Oct 23, 2024
- Updated
- Oct 24, 2024
- Vendor
- Botan Project
- Product
- Botan
- Classifications
- CWE-203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 23, 2024CVE publishedPublication date reported by the CVE source.
- Oct 24, 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 <3.6.0
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
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
- Breaking Bad: How Compilers Break Constant-Time Implementationsproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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