Security Digest · Critical advisory (no CVE assigned)
GHSA-346h-749j-r28w: PHPECC vulnerable to multiple cryptographic side-channel attacks
ECDSA Canonicalization PHPECC is vulnerable to malleable ECDSA signature attacks.
CVSS 9.1 Critical GitHub-reviewed · critical
Should you act?
- Only if you depend on one of the packages below, directly or transitively, in a vulnerable version. Check your lockfile with
composer audit. - No CVE has been assigned, so it will not appear in CVE-based scanners that ignore GitHub advisories.
npm audit,pip-auditand Dependabot do read GitHub advisories.
Affected packages
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Composer (PHP) | mdanter/ecc | >= 0, <= 1.0.0 | none listed |
Details
ECDSA Canonicalization
PHPECC is vulnerable to malleable ECDSA signature attacks.
Constant-Time Signer
When generating a new ECDSA signature, the GMPMath adapter was used. This class wraps the GNU Multiple Precision arithmetic library (GMP), which does not aim to provide constant-time implementations of algorithms.
An attacker capable of triggering many signatures and studying the time it takes to perform each operation would be able to leak the secret number, k, and thereby learn the private key.
EcDH Timing Leaks
When calculating a shared secret using the EcDH class, the scalar-point multiplication is based on the arithmetic defined by the Point class.
Even though the library implements a Montgomery ladder, the add(), mul(), and getDouble() methods on the Point class are not constant-time. This means that your ECDH private keys are leaking information about each bit of your private key through a timing side-channel.
CVSS: 9.1 (v3.1) CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Sources and references
- GitHub Advisory GHSA-346h-749j-r28w github.com
- github.com github.com
- github.com github.com
Critical Composer (PHP) advisories · Today’s Security Digest