Debian DSA-4387-1 : openssh - security update

medium Nessus Plugin ID 122068

Synopsis

The remote Debian host is missing a security-related update.

Description

Harry Sintonen from F-Secure Corporation discovered multiple vulnerabilities in OpenSSH, an implementation of the SSH protocol suite. All the vulnerabilities are in found in the scp client implementing the SCP protocol.

- CVE-2018-20685 Due to improper directory name validation, the scp client allows servers to modify permissions of the target directory by using empty or dot directory name.

- CVE-2019-6109 Due to missing character encoding in the progress display, the object name can be used to manipulate the client output, for example to employ ANSI codes to hide additional files being transferred.

- CVE-2019-6111 Due to scp client insufficient input validation in path names sent by server, a malicious server can do arbitrary file overwrites in target directory. If the recursive (-r) option is provided, the server can also manipulate subdirectories as well.

The check added in this version can lead to regression if the client and the server have differences in wildcard expansion rules. If the server is trusted for that purpose, the check can be disabled with a new -T option to the scp client.

Solution

Upgrade the openssh packages.

For the stable distribution (stretch), these problems have been fixed in version 1:7.4p1-10+deb9u5.

See Also

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=793412

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=919101

https://security-tracker.debian.org/tracker/CVE-2018-20685

https://security-tracker.debian.org/tracker/CVE-2019-6109

https://security-tracker.debian.org/tracker/CVE-2019-6111

https://security-tracker.debian.org/tracker/source-package/openssh

https://packages.debian.org/source/stretch/openssh

https://www.debian.org/security/2019/dsa-4387

Plugin Details

Severity: Medium

ID: 122068

File Name: debian_DSA-4387.nasl

Version: 1.5

Type: local

Agent: unix

Published: 2/11/2019

Updated: 5/24/2022

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.0

CVSS v2

Risk Factor: Medium

Base Score: 5.8

Temporal Score: 4.5

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

CVSS Score Source: CVE-2019-6111

CVSS v3

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 6.1

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

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

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:openssh, cpe:/o:debian:debian_linux:9.0

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 2/9/2019

Vulnerability Publication Date: 1/10/2019

Reference Information

CVE: CVE-2018-20685, CVE-2019-6109, CVE-2019-6111

DSA: 4387