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Security Bulletin: Redirect HTTP traffic vulnerability may affect IBM HTTP Server (CVE-2016-5387)

Security Bulletin


Summary

There is a vulnerability that allows redirecting of HTTP traffic with CGI applications that may affect IBM HTTP Server (IHS). This vulnerability is known as "HTTPOXY".

Vulnerability Details

CVEID: CVE-2016-5387
DESCRIPTION:
Apache HTTP Server could allow a remote attacker to redirect HTTP traffic of CGI application, caused by the lack of protection of untrusted client data in the HTTP_PROXY environment variable. By using a specially-crafted Proxy header in a HTTP request, a remote attacker could exploit this vulnerability to redirect outbound HTTP traffic to arbitrary proxy server, also known as the "HTTPOXY" vulnerability.
CVSS Base Score: 8.1
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/115090 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)

Affected Products and Versions

This vulnerability affects the following versions and releases of IBM HTTP Server (powered by Apache) component in all editions of WebSphere Application Server and bundling products.

  • Version 9.0
  • Version 8.5.5
  • Version 8.5
  • Version 8.0
  • Version 7.0

Remediation/Fixes

The APAR for this vulnerability is PI65855 and this is included in the interim fix for PI66849. Please refer to the Security bulletin for Denial of Service in Expat for more information on PI66849.

For affected IBM HTTP Server for WebSphere Application Server: The recommended solution is to apply the interim fix, Fix Pack or PTF containing APAR PI66849 for each named product as soon as practical.

For V9.0.0.0
:

· Apply Interim Fix PI66849

--OR--
· Apply Fix Pack 9.0.0.1 or later.

For V8.5.0.0 through 8.5.5.10:

· Upgrade to minimum fix pack levels as required by interim fix and then apply Interim Fix PI66849

--OR--
· Apply Fix Pack 8.5.5.11 or later.


For V8.0.0.0 through 8.0.0.12:

· Upgrade to minimum fix pack levels as required by interim fix and then apply Interim Fix PI66849

--OR--
· Apply Fix Pack 8.0.0.13 or later.


For V7.0.0.0 through 7.0.0.41:

· Upgrade to minimum fix pack levels as required by interim fix and then apply Interim Fix PI66849

--OR--
· Apply Fix Pack 7.0.0.43 or later.

For unsupported versions of the above products, IBM recommends upgrading to a fixed, supported version of the product.

Workarounds and Mitigations

For affected IBM HTTP Server for WebSphere Application Server:

If you use CGI or Fast CGI then you may be vulnerable

For Version 7.0 and later of IBM HTTP Server:

To mitigate around this issue you can update your IHS configuration.
Make sure that mod_header is loaded, then append the following to httpd.conf:

  RequestHeader unset Proxy early


For Version 6.1 or earlier of IBM HTTP Server:
To mitigate around this issue you can update your IHS configuration.
Make sure that mod_header is loaded, then append the following to httpd.conf:

  RequestHeader unset Proxy

Get Notified about Future Security Bulletins

References

Complete CVSS v3 Guide
On-line Calculator v3

Related information

IBM Secure Engineering Web Portal
IBM Product Security Incident Response Blog

Change History

28 July 2016: original document published
01 August 2016: updated score and vectors
16 August 2016: updated with interim fixes
17 August 2016: updated fixpack level to include 8.5.5.10
6 September 2016: updated workaround section
13 September 2016: update fixpack release dates

*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.

Disclaimer

According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES "AS IS" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY.

Cross reference information
Segment Product Component Platform Version Edition
Application Servers WebSphere Application Server

Document information

More support for: IBM HTTP Server

Software version: 7.0, 8.0, 8.5, 8.5.5, 9.0

Operating system(s): AIX, HP-UX, IBM i, Linux, Solaris, Windows, z/OS

Software edition: All Editions

Reference #: 1988019

Modified date: 13 September 2016


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