FreeBSD: VID-C6F4177C-8E29-11EF-98E7-84A93843EB75 (CVE-2024-9143): OpenSSL -- OOB memory access vulnerability

Description

Issue summary: Use of the low-level GF(2^m) elliptic curve APIs with untrusted

explicit values for the field polynomial can lead to out-of-bounds memory reads

or writes.

Impact summary: Out of bound memory writes can lead to an application crash or

even a possibility of a remote code execution, however, in all the protocols

involving Elliptic Curve Cryptography that we're aware of, either only "named

curves" are supported, or, if explicit curve parameters are supported, they

specify an X9.62 encoding of binary (GF(2^m)) curves that can't represent

problematic input values. Thus the likelihood of existence of a vulnerable

application is low.

In particular, the X9.62 encoding is used for ECC keys in X.509 certificates,

so problematic inputs cannot occur in the context of processing X.509

certificates. Any problematic use-cases would have to be using an "exotic"

curve encoding.

The affected APIs include: EC_GROUP_new_curve_GF2m(), EC_GROUP_new_from_params(),

and various supporting BN_GF2m_*() functions.

Applications working with "exotic" explicit binary (GF(2^m)) curve parameters,

that make it possible to represent invalid field polynomials with a zero

constant term, via the above or similar APIs, may terminate abruptly as a

result of reading or writing outside of array bounds. Remote code execution

cannot easily be ruled out.

The FIPS modules in 3.3, 3.2, 3.1 and 3.0 are not affected by this issue.