CVE-2017-2295

Versions of Puppet prior to 4.10.1 will deserialize data off the wire (from the agent to the server, in this case) with a attacker-specified format. This could be used to force YAML deserialization in an unsafe manner, which would lead to remote code execution. This change constrains the format of data on the wire to PSON or safely decoded YAML.

It was discovered that unrestricted YAML deserialisation of data sent from agents to the server in the Puppet configuration management system could result in the execution of arbitrary code (CVE-2017-2295).

This update for puppet fixes the following issues:

Security issue fixed:

• CVE-2017-2295: Possible code execution vulnerability where an attacker could force YAML deserialization in an unsafe manner. In default, this update breaks a backwards compatibility with Puppet agents older than 3.2.2 as the SLE12 master doesn't support other fact formats than pson in default anymore. In order to allow users to continue using their SLE12 master/SLE11 agents setup and fix CVE-2017-2295 for the others, a new puppet master boolean option 'dangerous_fact_formats' was added. When it's set to true it enables using dangerous fact formats (e.g. YAML). When it's set to false, only PSON fact format is accepted. (bsc#1040151)

This update for puppet fixes the following issues:

• CVE-2017-2295: Fixed a security vulnerability where an attacker could force YAML deserialization in an unsafe manner, which would lead to remote code execution.

In default, this update would break a backwards compatibility with Puppet agents older than 3.2.2 as the SLE11 master doesn't support other fact formats than pson in default anymore. In order to allow users to continue using their SLE11 agents a patch was added that enables sending PSON from agents.

For non-SUSE clients older that 3.2.2 a new puppet master boolean option 'dangerous_fact_formats' was added. When it's set to true it enables using dangerous fact formats (e.g. YAML). When it's set to false, only PSON fact format is accepted. (bsc#1040151), (bsc#1077767)

Dennis Rowe discovered that Puppet incorrectly handled the search path. A local attacker could use this issue to possibly execute arbitrary code. (CVE-2014-3248)

It was discovered that Puppet incorrectly handled YAML deserialization. A remote attacker could possibly use this issue to execute arbitrary code on the master. This update is incompatible with agents older than 3.2.2. (CVE-2017-2295)

It was discovered that Puppet installed modules with world writable permissions. An attacker could use this vulnerability to execute arbitrary code or cause a denial of service. (CVE-2017-10689)

It was discovered that Puppet could be used to force YAML deserialization in an unsafe manner. A remote attacker could use this vulnerability for remote code execution. (CVE-2017-2295)