Multiple timing variability issues in operations intended to be constant-time
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 0.7.6
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
This vulnerability affects crypto-math software that performs arithmetic on secret integers, such as big-integer and modular arithmetic libraries, where operations meant to run in constant time can instead leak information. An attacker who can observe timing or microarchitectural side effects could potentially learn intermediate values or secret data, which could in some cases help recover cryptographic keys.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
Several operations intended to be constant-time could execute secret-dependent branches, depending on the compiler and target CPU. These include subtraction, zero counting, division, and Montgomery multiplication. Additionally, `UintRef` equality could terminate at the first unequal limb, and `BoxedMontyForm::invert` branched on whether an inverse exists. Impact Applications using affected operations on secret integers may leak information through timing or microarchitectural side channels. This includes information about intermediate arithmetic values, matching limbs, and invertibility. Such leakage could potentially enable recovery of cryptographic secrets. Practical exploitability depends on the downstream algorithm, compiler, target CPU, and an attacker's ability to observe the side channel. Resolution Upgrade to v0.7.6, which removes the identified branches, updates `ctutils` to include its constant-time fixes, and adds BINSEC-based regression checks using `cargo checkct` for arithmetic on multiple targets.
Timeline
- Advisory published
- Record last updated
- First seen by cve.now
Affected versions
- crypto-bigintcrates.io
From 0.0.0-0 · fixed in 0.7.6