CVE-2016-2126

Publication date 19 December 2016

Last updated 24 July 2024

Ubuntu priority

Cvss 3 Severity Score

Samba version 4.0.0 up to 4.5.2 is vulnerable to privilege elevation due to incorrect handling of the PAC (Privilege Attribute Certificate) checksum. A remote, authenticated, attacker can cause the winbindd process to crash using a legitimate Kerberos ticket. A local service with access to the winbindd privileged pipe can cause winbindd to cache elevated access permissions.

From the Ubuntu Security Team

Volker Lendecke discovered that Kerberos PAC validation implementation in Samba contained multiple vulnerabilities. An authenticated attacker could use this to cause a denial of service or gain administrative privileges.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
samba	17.04 zesty	Fixed 2:4.4.5+dfsg-2ubuntu7
	16.10 yakkety	Fixed 2:4.4.5+dfsg-2ubuntu5.2
	16.04 LTS xenial	Fixed 2:4.3.11+dfsg-0ubuntu0.16.04.3
	14.04 LTS trusty	Fixed 2:4.3.11+dfsg-0ubuntu0.14.04.4
	12.04 LTS precise	Not affected
samba4	17.04 zesty	Not in release
	16.10 yakkety	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
	12.04 LTS precise	Ignored end of life

Notes

mdeslaur

4.0.0+

Severity score breakdown

Parameter	Value
Base score	6.5 · Medium
Attack vector	Network
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

USN-3158-1
Samba vulnerabilities
19 December 2016