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             AUSCERT External Security Bulletin Redistribution

                   Jenkins Security Advisory 2016-05-11
                                12 May 2016


        AusCERT Security Bulletin Summary

Product:           jenkins
Publisher:         jenkins
Operating System:  Windows
                   UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Execute Arbitrary Code/Commands -- Existing Account
                   Access Privileged Data          -- Existing Account
                   Denial of Service               -- Existing Account
                   Provide Misleading Information  -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2016-3727 CVE-2016-3726 CVE-2016-3725
                   CVE-2016-3724 CVE-2016-3723 CVE-2016-3722

Original Bulletin: 

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Jenkins Security Advisory 2016-05-11

    Added by Daniel Beck, last edited by Daniel Beck on May 11, 2016

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This advisory announces multiple vulnerabilities in Jenkins.


Arbitrary build parameters are passed to build scripts as environment 

SECURITY-170 / CVE-2016-3721

Build parameters in Jenkins typically are passed to build scripts as 
environment variables. Some plugins allow passing arbitrary (undeclared) 
parameters. Depending on access permissions and installed plugins, malicious 
users were able to trigger builds, passing arbitrary environment variables 
(e.g. PATH) to modify the behavior of those builds. Rather than expect all 
plugin authors to be aware of this potential problem, Jenkins now filters the
build parameters based on what is defined on the job.

As this change is known to affect a number of plugins, it's possible to 
restore the previous behavior by setting the system property 
hudson.model.ParametersAction.keepUndefinedParameters to true. This is 
potentially very unsafe and intended as a short-term workaround only.

To allow specific, known safe parameter names to be passed to builds, set the
system property hudson.model.ParametersAction.safeParameters to a 
comma-separated list of safe parameter names. Example:

java -Dhudson.model.ParametersAction.safeParameters=FOO,BAR_BAZ,qux -jar 

Malicious users with multiple user accounts can prevent other users from 
logging in

SECURITY-243 / CVE-2016-3722

By changing the freely editable 'full name', malicious users with multiple 
user accounts could prevent other users from logging in, as 'full name' was 
resolved before actual user name to determine which account is currently 
trying to log in. Information on installed plugins exposed via API

SECURITY-250 / CVE-2016-3723

The XML/JSON API endpoints providing information about installed plugins were
missing permissions checks, allowing any user with read access to Jenkins to 
determine which plugins and versions were installed. Encrypted secrets (e.g. 
passwords) were leaked to users with permission to read configuration

SECURITY-266 / CVE-2016-3724

Users with extended read access could access encrypted secrets stored directly
in the configuration of those items.

As a side-effect of this change, copying a job that contains secrets in its 
configuration now requires the Configure permission on that job. Regular users
can trigger download of update site metadata

SECURITY-273 / CVE-2016-3725

A missing permissions check allowed any user with access to Jenkins to trigger
an update of update site metadata. This could be combined with DNS cache 
poisoning to disrupt Jenkins service. Open redirect to scheme-relative URLs

SECURITY-276 / CVE-2016-3726

Some Jenkins URLs did not properly validate the redirect URLs, which allowed 
malicious users to create URLs that redirect users to arbitrary 
scheme-relative URLs. Granting the permission to read node configurations 
allows access to overall system configuration

SECURITY-281 / CVE-2016-3727

The API URL /computer/(master)/api/xml allowed users with the 'extended read'
permission for the master node to see some global Jenkins configuration, 
including the configuration of the security realm.

This URL now unconditionally sends HTTP 400 Bad Request when accessed. There 
is no workaround.


    SECURITY-170 is considered medium.

    SECURITY-243 is considered low.

    SECURITY-250 is considered medium.

    SECURITY-266 is considered medium.

    SECURITY-273 is considered low.

    SECURITY-276 is considered medium.

    SECURITY-281 is considered medium.

Affected versions

    All Jenkins main line releases up to and including 2.2

    All Jenkins LTS releases up to and including 1.651.1


    Jenkins main line users should update to 2.3

    Jenkins LTS users should update to 1.651.2

These versions include fixes to all the vulnerabilities described above. All 
prior versions are affected by these vulnerabilities. Credit

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

    Adam Cazzolla and Ben Bleiberg, Sonatype Inc. for SECURITY-276

    Charles Nelson for SECURITY-250

    James Nord, CloudBees, Inc. for SECURITY-273

    Jesse Glick, CloudBees, Inc. for SECURITY-281

    Stephen Connolly, CloudBees, Inc. for SECURITY-170

    Steve Marlowe <smarlowe@cisco.com> of Cisco ASIG for SECURITY-243 and 

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