Amazon Linux AMI : ruby20 / ruby21,ruby24 (ALAS-2019-1255)

high Nessus Plugin ID 127811


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


An issue was discovered in RubyGems. The gem owner command outputs the contents of the API response directly to stdout. Therefore, if the response is crafted, escape sequence injection may occur.(CVE-2019-8322)

An issue was discovered in RubyGems.
Gem::GemcutterUtilities#with_response may output the API response to stdout as it is. Therefore, if the API side modifies the response, escape sequence injection may occur.(CVE-2019-8323)

An issue was discovered in RubyGems. Since Gem::UserInteraction#verbose calls say without escaping, escape sequence injection is possible.(CVE-2019-8321)

A Directory Traversal issue was discovered in RubyGems. Before making new directories or touching files (which now include path-checking code for symlinks), it would delete the target destination. If that destination was hidden behind a symlink, a malicious gem could delete arbitrary files on the user's machine, presuming the attacker could guess at paths. Given how frequently gem is run as sudo, and how predictable paths are on modern systems (/tmp, /usr, etc.), this could likely lead to data loss or an unusable system.(CVE-2019-8320)

An issue was discovered in RubyGems. A crafted gem with a multi-line name is not handled correctly. Therefore, an attacker could inject arbitrary code to the stub line of gemspec, which is eval-ed by code in ensure_loadable_spec during the preinstall check.(CVE-2019-8324)

An issue was discovered in RubyGems. Since Gem::CommandManager#run calls alert_error without escaping, escape sequence injection is possible. (There are many ways to cause an error.)(CVE-2019-8325)


Run 'yum update ruby20' to update your system.

Run 'yum update ruby21' to update your system.

Run 'yum update ruby24' to update your system.

See Also

Plugin Details

Severity: High

ID: 127811

File Name: ala_ALAS-2019-1255.nasl

Version: 1.2

Type: local

Agent: unix

Published: 8/13/2019

Updated: 1/2/2020

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

Risk Information

CVSS Score Source: CVE-2019-8320


Risk Factor: Medium

Score: 5.9


Risk Factor: High

Base Score: 8.8

Temporal Score: 6.5

Vector: AV:N/AC:M/Au:N/C:N/I:C/A:C

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


Risk Factor: High

Base Score: 7.4

Temporal Score: 6.4

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

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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:ruby20, p-cpe:/a:amazon:linux:ruby20-debuginfo, p-cpe:/a:amazon:linux:ruby20-devel, p-cpe:/a:amazon:linux:ruby20-doc, p-cpe:/a:amazon:linux:ruby20-irb, p-cpe:/a:amazon:linux:ruby20-libs, p-cpe:/a:amazon:linux:ruby21, p-cpe:/a:amazon:linux:ruby21-debuginfo, p-cpe:/a:amazon:linux:ruby21-devel, p-cpe:/a:amazon:linux:ruby21-doc, p-cpe:/a:amazon:linux:ruby21-irb, p-cpe:/a:amazon:linux:ruby21-libs, p-cpe:/a:amazon:linux:ruby24, p-cpe:/a:amazon:linux:ruby24-debuginfo, p-cpe:/a:amazon:linux:ruby24-devel, p-cpe:/a:amazon:linux:ruby24-doc, p-cpe:/a:amazon:linux:ruby24-irb, p-cpe:/a:amazon:linux:ruby24-libs, p-cpe:/a:amazon:linux:rubygem20-bigdecimal, p-cpe:/a:amazon:linux:rubygem20-io-console, p-cpe:/a:amazon:linux:rubygem20-psych, p-cpe:/a:amazon:linux:rubygem21-bigdecimal, p-cpe:/a:amazon:linux:rubygem21-io-console, p-cpe:/a:amazon:linux:rubygem21-psych, p-cpe:/a:amazon:linux:rubygem24-bigdecimal, p-cpe:/a:amazon:linux:rubygem24-did_you_mean, p-cpe:/a:amazon:linux:rubygem24-io-console, p-cpe:/a:amazon:linux:rubygem24-json, p-cpe:/a:amazon:linux:rubygem24-psych, p-cpe:/a:amazon:linux:rubygem24-xmlrpc, p-cpe:/a:amazon:linux:rubygems20, p-cpe:/a:amazon:linux:rubygems20-devel, p-cpe:/a:amazon:linux:rubygems21, p-cpe:/a:amazon:linux:rubygems21-devel, p-cpe:/a:amazon:linux:rubygems24, p-cpe:/a:amazon:linux:rubygems24-devel, cpe:/o:amazon:linux

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

Exploit Ease: No known exploits are available

Patch Publication Date: 8/12/2019

Vulnerability Publication Date: 6/6/2019

Reference Information

CVE: CVE-2019-8320, CVE-2019-8321, CVE-2019-8322, CVE-2019-8323, CVE-2019-8324, CVE-2019-8325

ALAS: 2019-1255