Ubuntu 16.04 LTS : Rsyslog vulnerabilities (USN-5419-1)

critical Nessus Plugin ID 161170

Synopsis

The remote Ubuntu host is missing one or more security updates.

Description

The remote Ubuntu 16.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5419-1 advisory.

- A denial of service vulnerability was found in rsyslog in the imptcp module. An attacker could send a specially crafted message to the imptcp socket, which would cause rsyslog to crash. Versions before 8.27.0 are vulnerable. (CVE-2018-16881)

- An issue was discovered in Rsyslog v8.1908.0. contrib/pmaixforwardedfrom/pmaixforwardedfrom.c has a heap overflow in the parser for AIX log messages. The parser tries to locate a log message delimiter (in this case, a space or a colon) but fails to account for strings that do not satisfy this constraint. If the string does not match, then the variable lenMsg will reach the value zero and will skip the sanity check that detects invalid log messages. The message will then be considered valid, and the parser will eat up the nonexistent colon delimiter. In doing so, it will decrement lenMsg, a signed integer, whose value was zero and now becomes minus one. The following step in the parser is to shift left the contents of the message. To do this, it will call memmove with the right pointers to the target and destination strings, but the lenMsg will now be interpreted as a huge value, causing a heap overflow. (CVE-2019-17041)

- An issue was discovered in Rsyslog v8.1908.0. contrib/pmcisconames/pmcisconames.c has a heap overflow in the parser for Cisco log messages. The parser tries to locate a log message delimiter (in this case, a space or a colon), but fails to account for strings that do not satisfy this constraint. If the string does not match, then the variable lenMsg will reach the value zero and will skip the sanity check that detects invalid log messages. The message will then be considered valid, and the parser will eat up the nonexistent colon delimiter. In doing so, it will decrement lenMsg, a signed integer, whose value was zero and now becomes minus one. The following step in the parser is to shift left the contents of the message.
To do this, it will call memmove with the right pointers to the target and destination strings, but the lenMsg will now be interpreted as a huge value, causing a heap overflow. (CVE-2019-17042)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

https://ubuntu.com/security/notices/USN-5419-1

Plugin Details

Severity: Critical

ID: 161170

File Name: ubuntu_USN-5419-1.nasl

Version: 1.2

Type: local

Agent: unix

Published: 5/13/2022

Updated: 5/13/2022

Supported Sensors: Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent

Risk Information

CVSS Score Source: CVE-2019-17042

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P

Temporal Vector: E:U/RL:OF/RC:C

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:rsyslog, p-cpe:/a:canonical:ubuntu_linux:rsyslog-elasticsearch, p-cpe:/a:canonical:ubuntu_linux:rsyslog-gnutls, p-cpe:/a:canonical:ubuntu_linux:rsyslog-gssapi, p-cpe:/a:canonical:ubuntu_linux:rsyslog-mysql, p-cpe:/a:canonical:ubuntu_linux:rsyslog-pgsql, p-cpe:/a:canonical:ubuntu_linux:rsyslog-relp

Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 5/12/2022

Vulnerability Publication Date: 1/25/2019

Reference Information

CVE: CVE-2018-16881, CVE-2019-17041, CVE-2019-17042

USN: 5419-1