Security Advisories » Jenkins Security Advisory 2019-01-28

Jenkins Security Advisory 2019-01-28

This advisory announces vulnerabilities in the following Jenkins deliverables:

Descriptions

Sandbox Bypass in Script Security Plugin

SECURITY-1292 / CVE-2019-1003005

Script Security sandbox protection could be circumvented during the script compilation phase by applying AST transforming annotations such as @Grab to source code elements.

This affected an HTTP endpoint used to validate a user-submitted Groovy script that was not covered in the 2019-01-08 fix for SECURITY-1266 and allowed users with Overall/Read permission to bypass the sandbox protection and execute arbitrary code on the Jenkins master.

The affected HTTP endpoint now applies a safe Groovy compiler configuration prohibiting unsafe AST transforming annotations.

Sandbox Bypass in Groovy Plugin

SECURITY-1293 / CVE-2019-1003006

Groovy Plugin has a form validation HTTP endpoint used to validate a user-submitted Groovy script through compilation, which was not subject to sandbox protection. This allowed attackers with Overall/Read access to execute arbitrary code on the Jenkins master by applying AST transforming annotations such as @Grab to source code elements.

The affected HTTP endpoint now applies a safe Groovy compiler configuration preventing the use of unsafe AST transforming annotations.

Sandbox Bypass via CSRF in Warnings Plugin

SECURITY-1295 (1) / CVE-2019-1003007

Warnings Plugin has a form validation HTTP endpoint used to validate a user-submitted Groovy script through compilation, which was not subject to sandbox protection. The endpoint checked for the Overall/RunScripts permission, but did not require POST requests, so it was vulnerable to cross-site request forgery (CSRF). This allowed attackers to execute arbitrary code on the Jenkins master by applying AST transforming annotations such as @Grab to source code elements.

The affected HTTP endpoint now applies a safe Groovy compiler configuration preventing the use of unsafe AST transforming annotations. Additionally, the form validation HTTP endpoint now requires that requests be sent via POST to prevent CSRF.

Sandbox Bypass via CSRF in Warnings Next Generation Plugin

SECURITY-1295 (2) / CVE-2019-1003008

Warnings Next Generation Plugin has a form validation HTTP endpoint used to validate a Groovy script through compilation, which was not subject to sandbox protection. The endpoint checked for the Overall/RunScripts permission, but did not require POST requests, so it was vulnerable to cross-site request forgery (CSRF). This allowed attackers to execute arbitrary code on the Jenkins master by applying AST transforming annotations such as @Grab to source code elements.

The affected HTTP endpoint now applies a safe Groovy compiler configuration preventing the use of unsafe AST transforming annotations. Additionally, the form validation HTTP endpoint now requires that requests be sent via POST to prevent CSRF.

Improper certificate validation with StartTLS in Active Directory Plugin

SECURITY-859 / CVE-2019-1003009

Active Directory Plugin performs TLS upgrade (StartTLS) after connecting to domain controllers through insecure LDAP. In this mode, certificates were not properly validated, effectively trusting all certificates, allowing man-in-the-middle attacks.

This only affected TLS upgrades. The LDAPS mode, available by setting the system property hudson.plugins.active_directory.ActiveDirectorySecurityRealm.forceLdaps to true, was unaffected.

The plugin now properly validates certificates according to the TLS trust configuration when performing a TLS upgrade.

CSRF vulnerability in Git Plugin

SECURITY-1095 / CVE-2019-1003010

Git Plugin allows the creation of a tag in a job workspace’s Git repository with accompanying metadata attached to a build record.

The HTTP endpoint to create the tag did not require POST requests, resulting in a CSRF vulnerability.

The HTTP endpoint to create the tag now requires that requests are sent via POST.

Recursive token expansion results in information disclosure and DoS in Token Macro Plugin

SECURITY-1102 / CVE-2019-1003011

Token Macro Plugin recursively applied token expansion.

This could be used by users able to affect input to token expansion (such as change log messages), to inject additional tokens into the input, which would then be expanded, resulting in information disclosure (for example values of environment variables), or denial of service.

Most tokens have been changed to no longer recursively apply token expansion.

Blue Ocean did not require CSRF tokens

SECURITY-1201 / CVE-2019-1003012

Blue Ocean did not require CSRF tokens ("crumbs") for POST requests with the Content-Type: application/json.

Blue Ocean now requires that valid CSRF tokens are present in POST requests.

XSS vulnerability via user description in Blue Ocean

SECURITY-1204 / CVE-2019-1003013

Blue Ocean did not properly escape HTML/JavaScript content set on the current user’s description field, resulting in a cross-site scripting vulnerability exploitable by administrators and other people accessing Jenkins with the same user account.

Blue Ocean now properly escapes HTML/JavaScript content set on the current user’s description field.

XSS vulnerability in Config File Provider Plugin

SECURITY-1253 / CVE-2019-1003014

Config File Provider Plugin improperly handled script names in its JavaScript-based UI, resulting in a stored cross-site scripting (XSS) vulnerability.

Config File Provider Plugin now properly handles script names.

XXE vulnerability in Job Import Plugin

SECURITY-905 (1) / CVE-2019-1003015

Job Import Plugin allows to import jobs from other Jenkins instances. As a first step in this process, Job Import Plugin sends a request to another Jenkins instance, parsing XML REST API output to obtain a list of jobs that could be imported.

Job Import Plugin did not configure the XML parser in a way that would prevent XML External Entity (XXE) processing. This allowed attackers able to control either the server Jenkins will query, or the URL Jenkins queries, to have it parse a maliciously crafted XML response that uses external entities for extraction of secrets from the Jenkins master, server-side request forgery, or denial-of-service attacks.

External entity resolution has been disabled for the XML parser used in Job Import Plugin 3.0.

CSRF vulnerability and missing permission checks in Job Import Plugin allowed capturing credentials

SECURITY-905 (2) / CVE-2019-1003016

Job Import Plugin did not check user permissions on its API endpoint used to access remote Jenkins instances. This allowed users with Overall/Read access to Jenkins to connect to an attacker-specified URL using attacker-specified credentials IDs obtained through another method, capturing credentials stored in Jenkins.

Job Import Plugin 3.0 will only access Jenkins instances using credentials defined in the global configuration.

CSRF vulnerability in Job Import Plugin allowed creating and overwriting jobs, installing some plugins

SECURITY-1302 / CVE-2019-1003017

Job Import Plugin did not require that POST requests are sent to its /import URL, which processes requests to import jobs. This resulted in a cross-site request forgery (CSRF) vulnerability that could be exploited to create or replace jobs on the local instance if the remote Jenkins instance has different ones with the same name, or to install additional plugins, if jobs on the remote Jenkins instance reference them in their configuration.

Job Import Plugin 3.0 restricted which remote Jenkins instances jobs can be imported from, limiting how this can be exploited. From Job Import Plugin 3.1, the /import URL requires that requests are sent via POST.

GitHub Authentication Plugin showed plain text client secret in configuration form

SECURITY-602 / CVE-2019-1003018

GitHub Authentication Plugin stores the client secret in the global Jenkins configuration.

While the client secret is stored encrypted on disk, it was transmitted in plain text as part of the configuration form and displayed without masking. This could result in exposure of the client secret through browser extensions, cross-site scripting vulnerabilities, and similar situations.

GitHub Authentication Plugin now encrypts the client secret transmitted to administrators viewing the global security configuration form.

Session fixation vulnerability in GitHub Authentication Plugin

SECURITY-797 / CVE-2019-1003019

GitHub Authentication Plugin did not invalidate the previous session and create a new one upon successful login, allowing attackers able to control or obtain another user’s pre-login session ID to impersonate them.

GitHub Authentication Plugin now invalidates the previous session during login and creates a new one.

CSRF vulnerability and missing permission checks in Kanboard Plugin allowed server-side request forgery

SECURITY-818 / CVE-2019-1003020

Kanboard Plugin did not perform permission checks on a method implementing form validation. This allowed users with Overall/Read access to Jenkins to submit a GET request to an attacker-specified URL.

Additionally, this form validation method did not require POST requests, resulting in a CSRF vulnerability.

This form validation method now requires POST requests and Overall/Administer permissions.

OpenId Connect Authentication Plugin showed plain text client secret in configuration form

SECURITY-886 / CVE-2019-1003021

OpenId Connect Authentication Plugin stores the client secret in the global Jenkins configuration.

While the client secret is stored encrypted on disk, it was transmitted in plain text as part of the configuration form and displayed without masking. This could result in exposure of the client secret through browser extensions, cross-site scripting vulnerabilities, and similar situations.

The OpenId Connect Authentication Plugin now encrypts the client secret transmitted to administrators viewing the global configuration form.

Monitoring Plugin did not apply CSRF protection even if enabled in Jenkins

SECURITY-1153 / CVE-2019-1003022

Monitoring Plugin provides a standalone JavaMelody servlet with an independent CSRF protection configuration. Even if Jenkins had CSRF protection enabled, Monitoring Plugin may not have it enabled.

Monitoring Plugin now checks on startup whether Jenkins has CSRF protection enabled and enables its own CSRF protection accordingly.

Note
Monitoring Plugin does not take into account configuration changes applied after Jenkins startup or after Monitoring Plugin finishes loading. Administrators need to restart Jenkins when enabling or disabling the CSRF protection configuration to apply the change to Monitoring Plugin.

Clickjacking vulnerability in Monitoring Plugin

SECURITY-1154

Monitoring Plugin did not set the X-Frame-Options header, allowing its pages to be embedded. This could result in clickjacking attacks.

Monitoring Plugin now sets the X-Frame-Options header to sameorigin, preventing embedding.

XSS vulnerability in Warnings Next Generation Plugin

SECURITY-1271 / CVE-2019-1003023

Warnings Next Generation Plugin did not properly escape HTML content in warnings displayed on the Jenkins UI, resulting in a cross-site scripting vulnerability exploitable by users able to control warnings parser input.

Warnings Next Generation Plugin now removes unsafe HTML content from warnings.

Severity

Affected Versions

  • Active Directory Plugin up to and including 2.10
  • Blue Ocean Plugin up to and including 1.10.1
  • Config File Provider Plugin up to and including 3.4.1
  • Git Plugin up to and including 3.9.1
  • GitHub Authentication Plugin up to and including 0.29
  • Groovy Plugin up to and including 2.0
  • Job Import Plugin up to and including 2.1
  • Job Import Plugin up to and including 3.0
  • Kanboard Plugin up to and including 1.5.10
  • Monitoring Plugin up to and including 1.74.0
  • OpenId Connect Authentication Plugin up to and including 1.4
  • Script Security Plugin up to and including 1.50
  • Token Macro Plugin up to and including 2.5
  • Warnings Plugin up to and including 5.0.0
  • Warnings Next Generation Plugin up to and including 2.1.1
  • Warnings Next Generation Plugin up to and including 1.0.1

Fix

  • Active Directory Plugin should be updated to version 2.11
  • Blue Ocean Plugin should be updated to version 1.10.2
  • Config File Provider Plugin should be updated to version 3.5
  • Git Plugin should be updated to version 3.9.2
  • GitHub Authentication Plugin should be updated to version 0.31
  • Groovy Plugin should be updated to version 2.1
  • Job Import Plugin should be updated to version 3.0
  • Job Import Plugin should be updated to version 3.1
  • Kanboard Plugin should be updated to version 1.5.11
  • Monitoring Plugin should be updated to version 1.75.0
  • OpenId Connect Authentication Plugin should be updated to version 1.5
  • Script Security Plugin should be updated to version 1.51
  • Token Macro Plugin should be updated to version 2.6
  • Warnings Plugin should be updated to version 5.0.1
  • Warnings Next Generation Plugin should be updated to version 2.1.2
  • Warnings Next Generation Plugin should be updated to version 2.0.0

These versions include fixes to the vulnerabilities described above. All prior versions are considered to be affected by these vulnerabilities unless otherwise indicated.

Credit

The Jenkins project would like to thank the reporters for discovering and reporting these vulnerabilities:

  • Adam Willard for SECURITY-1253
  • Andy Caldwell and Chris Swindle, Metaswitch Networks for SECURITY-1102
  • Chris Jacobs, Comscore, Inc., Systems Engineer for SECURITY-859
  • Daniel Beck, CloudBees, Inc. for SECURITY-1153, SECURITY-1154, SECURITY-1302
  • James Nord, CloudBees, Inc. for SECURITY-886
  • Kalle Niemitalo, Procomp Solutions Oy for SECURITY-1271
  • Man Shum ( https://www.instagram.com/evmannn/ ) from Hong Kong for SECURITY-1204
  • Mikhail Egorov, security researcher, https://twitter.com/0ang3el for SECURITY-1292
  • Oleg Nenashev for SECURITY-1095
  • R. Tyler Croy, CloudBees, Inc. for SECURITY-602
  • Thomas Chauchefoin and Julien Szlamowicz of Synacktiv for SECURITY-905 (1), SECURITY-905 (2)
  • Thomas de Grenier de Latour for SECURITY-818
  • Wadeck Follonier, CloudBees, Inc. for SECURITY-797, SECURITY-1201