[ASA-202007-6] libjcat: insufficient validation

[Morten Linderud]

Arch Linux Security Advisory ASA-202007-6
=========================================

Severity: High
Date    : 2020-07-31
CVE-ID  : CVE-2020-10759
Package : libjcat
Type    : insufficient validation
Remote  : Yes
Link    : https://security.archlinux.org/AVG-1185

Summary
=======

The package libjcat before version 0.1.3-1 is vulnerable to
insufficient validation.

Resolution
==========

Upgrade to 0.1.3-1.

# pacman -Syu "libjcat>=0.1.3-1"

The problem has been fixed upstream in version 0.1.3.

Workaround
==========

None.

Description
===========

A PGP signature verification bypass has been found in fwupd prior to
1.4.0, and in libjcat <= 0.1.2. The issue is that if a detached
signature is actually a PGP message, gpgme_op_verify() returns the
rather perplexing GPG_ERR_NO_ERROR, and then gpgme_op_verify_result()
builds an empty list.

Impact
======

A local attacker could pass signature validation with a crafted
message.

References
==========

https://github.com/justinsteven/advisories/blob/master/2020_fwupd_dangling_s3_bucket_and_CVE-2020-10759_signature_verification_bypass.md
https://github.com/hughsie/libjcat/commit/839b89f
https://security.archlinux.org/CVE-2020-10759
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <https://lists.archlinux.org/pipermail/arch-security/attachments/20200731/6aa77b1c/attachment.sig>