Bug 1901094 (CVE-2020-27780) - CVE-2020-27780 pam: authentication bypass when the user doesn't exist and root password is blank
Summary: CVE-2020-27780 pam: authentication bypass when the user doesn't exist and roo...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2020-27780
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1901173
Blocks: 1900800
TreeView+ depends on / blocked
 
Reported: 2020-11-24 13:41 UTC by Guilherme de Almeida Suckevicz
Modified: 2021-02-10 15:25 UTC (History)
4 users (show)

Fixed In Version: pam 1.5.1
Clone Of:
Environment:
Last Closed: 2020-11-24 17:34:06 UTC
Embargoed:

Attachments (Terms of Use)

Description Guilherme de Almeida Suckevicz 2020-11-24 13:41:15 UTC 
A flaw was found in Linux-Pam in the way it handle empty passwords for non-existing users. When the user doesn't exist PAM try to authenticate with root and in the case of an empty password it successfully authenticate.

Reference:
https://github.com/linux-pam/linux-pam/issues/284

Upstream patch:
https://github.com/linux-pam/linux-pam/pull/300
Comment 1 Stefan Cornelius 2020-11-24 16:25:18 UTC 
Introduced in version 1.5.0.
Comment 2 Stefan Cornelius 2020-11-24 16:32:01 UTC 
Created pam tracking bugs for this issue:

Affects: fedora-all [bug 1901173]
Comment 3 Product Security DevOps Team 2020-11-24 17:34:06 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2020-27780
Note You need to log in before you can comment on or make changes to this bug.