Amazon Linux AMI : usermode / libuser (ALAS-2015-572)

High Nessus Plugin ID 84964


The remote Amazon Linux AMI host is missing a security update.


It was found that libuser, as used in the chfn userhelper functionality, does not properly filter out newline characters, which allows an authenticated local attacker to corrupt the /etc/passwd file and cause denial-of-service against the system. (CVE-2015-3245)

A flaw was found in the way the libuser library handled the /etc/passwd file. A local attacker could use an application compiled against libuser (for example, userhelper) to manipulate the /etc/passwd file, which could result in a denial of service or possibly allow the attacker to escalate their privileges to root.


Run 'yum update usermode libuser' to update your system.

See Also

Plugin Details

Severity: High

ID: 84964

File Name: ala_ALAS-2015-572.nasl

Version: 2.13

Type: local

Agent: unix

Published: 2015/07/24

Updated: 2018/05/15

Dependencies: 12634

Risk Information

Risk Factor: High

CVSS v2.0

Base Score: 7.2

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:C/A:C

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:libuser, p-cpe:/a:amazon:linux:libuser-debuginfo, p-cpe:/a:amazon:linux:libuser-devel, p-cpe:/a:amazon:linux:libuser-python, p-cpe:/a:amazon:linux:usermode, p-cpe:/a:amazon:linux:usermode-debuginfo, cpe:/o:amazon:linux

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2015/07/23

Exploitable With

Core Impact

Metasploit (Libuser roothelper Privilege Escalation)

Reference Information

CVE: CVE-2015-3245, CVE-2015-3246

ALAS: 2015-572

IAVA: 2015-A-0179

RHSA: 2015:1482