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Signature validation bypass

Critical
woodruffw published GHSA-rc7g-99x7-4p9g Aug 9, 2023

Package

uthenticode (C++)

Affected versions

1.0.9

Patched versions

<1.0.9, >= 2.0.0

Description

Impact

Version 1.0.9 of uthenticode hashed the entire file rather than hashing sections by virtual address, in violation of the Authenticode specification. As a result, an attacker could modify code within a binary without changing its Authenticode hash, making it appear valid from uthenticode's perspective.

Versions of uthenticode prior to 1.0.9 are not vulnerable to this attack, nor are versions in the 2.x series.

By design, uthenticode does not perform full-chain validation. However, the malleability of signature verification introduced in 1.0.9 was an unintended oversight.

Patches

The 2.x series addresses the vulnerability. Versions prior to 1.0.9 are also not vulnerable, but users are encouraged to upgrade rather than downgrade.

Workarounds

There are no workarounds to this vulnerability. Users should upgrade to the 2.x series of uthenticode.

References

Forthcoming.

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

CVE ID

CVE-2023-39969

Weaknesses

Credits