Symlink Vulnerability in Yubico PAM U2F Authentication Middleware
CVE-2019-12209

7.5HIGH

Key Information:

Vendor

Yubico

Status
Pam-u2f
Vendor
CVE Published:
4 June 2019

What is CVE-2019-12209?

The Yubico pam-u2f version 1.0.7 exhibits a flaw in its handling of the authentication file, $HOME/.config/Yubico/u2f_keys. When the authentication file is parsed, it does so as root unless the 'openasuser' option is specifically enabled. Consequently, if a symlink exists that redirects to files owned by root, this could allow unintended access. Additionally, if the PAM configuration has the debug option activated, critical elements of the symlinked file’s content may inadvertently be logged, potentially exposing sensitive data.

References

https://github.com/Yubico/pam-u2f/commit/7db3386fcdb454e3...
x_refsource_CONFIRM
https://developers.yubico.com/pam-u2f/Release_Notes.html
x_refsource_CONFIRM
http://www.openwall.com/lists/oss-security/2019/06/05/1
mailing-listx_refsource_MLIST

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.