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

medium Nessus Plugin ID 84964

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Synopsis

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

Description

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.
(CVE-2015-3246)

Solution

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

See Also

https://alas.aws.amazon.com/ALAS-2015-572.html

Plugin Details

Severity: Medium

ID: 84964

File Name: ala_ALAS-2015-572.nasl

Version: 2.14

Type: Local

Agent: unix

Published: 7/24/2015

Updated: 8/26/2026

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.6

Percentile: 98.37

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 6.3

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

CVSS Score Source: CVE-2015-3246

CVSS v3

Risk Factor: Medium

Base Score: 5.1

Temporal Score: 4.9

Vector: CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:H/RL:O/RC:C

Vulnerability Information

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

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: 7/23/2015

CISA Known Exploited Vulnerability Due Dates: 9/9/2026

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