ESB-2018.3312 - [Appliance] F5 BIG-IP products: Denial of service - Remote/unauthenticated 2018-10-29

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2018.3312
  K12636: Slowloris denial-of-service attack vulnerability CVE-2007-6750
                              29 October 2018

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           F5 BIG-IP products
Publisher:         F5 Networks
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Mitigation
CVE Names:         CVE-2007-6750  

Reference:         ESB-2017.0818
                   ESB-2016.1388
                   ESB-2016.1114
                   ESB-2013.0533

Original Bulletin: 
   https://support.f5.com/csp/article/K12636

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K12636: Slowloris denial-of-service attack vulnerability CVE-2007-6750

Security Advisory


Original Publication Date: Feb 23, 2011
Updated Date: Oct 27, 2018

Security Advisory Description

The Apache HTTP Server 1.x and 2.x allows remote attackers to cause a denial of
service (daemon outage) via partial HTTP requests, as demonstrated by
Slowloris, related to the lack of the mod_reqtimeout module in versions before
2.2.15. (CVE-2007-6750)

Impact

The Slowloris attack is a type of denial-of-service (DoS) attack that targets
threaded web servers. It attempts to monopolize all of the available request
handling threads on the web server by sending HTTP requests that never
complete. Because each request consumes a thread, the Slowloris attack
eventually consumes all of the web server's connection capacity, effectively
denying access to legitimate users.

The HTTP protocol specification Internet Engineering Task Force (RFC 2616)
states that a blank line must be used to indicate the end of the request
headers and the beginning of the payload, if any. After the entire request is
received, the web server may then respond.

Note: A blank line is created by sending two consecutive newlines:

The Slowloris attack operates by establishing multiple connections to the web
server. On each connection, it sends an incomplete request that does not
include the terminating newline sequence. The attacker sends additional header
lines periodically to keep the connection alive, but never sends the
terminating newline sequence. The web server keeps the connection open,
expecting more information to complete the request. As the attack continues,
the volume of long-standing Slowloris connections increases, eventually
consuming all available web server connections, thus rendering the web server
unavailable to respond to legitimate requests.

Security Advisory Status

F5 Product Development has assigned IDs 222807, 433296, and 605420 (BIG-IP), ID
340793 (ARX), and ID 319213 (FirePass) to this vulnerability.

To determine if your release is known to be vulnerable, the components or
features that are affected by the vulnerability, and for information about
releases or hotfixes that address the vulnerability, refer to the following
table.

+--------------+-------------------+----------------------+-------------------+
|              |Versions known to  |Versions known to be  |Vulnerable         |
|Product       |be vulnerable      |not vulnerable        |component or       |
|              |                   |                      |feature            |
+--------------+-------------------+----------------------+-------------------+
|              |12.0.0 - 12.1.2    |13.0.0                |Management user    |
|BIG-IP LTM    |11.0.0 - 11.6.1    |12.1.2 HF1            |interface          |
|              |10.0.0 - 10.2.4    |                      |                   |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP AAM    |12.0.0 - 12.1.2    |13.0.0                |Management user    |
|              |11.4.0 - 11.6.1    |12.1.2 HF1            |interface          |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP AFM    |12.0.0 - 12.1.2    |13.0.0                |Management user    |
|              |11.3.0 - 11.6.1    |12.1.2 HF1            |interface          |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP        |12.0.0 - 12.1.2    |13.0.0                |Management user    |
|Analytics     |11.0.0 - 11.6.1    |12.1.2 HF1            |interface          |
+--------------+-------------------+----------------------+-------------------+
|              |12.0.0 - 12.1.2    |13.0.0                |Management user    |
|BIG-IP APM    |11.0.0 - 11.6.1    |12.1.2 HF1            |interface          |
|              |10.1.0 - 10.2.4    |                      |                   |
+--------------+-------------------+----------------------+-------------------+
|              |12.0.0 - 12.1.2    |13.0.0                |Management user    |
|BIG-IP ASM    |11.0.0 - 11.6.1    |12.1.2 HF1            |interface          |
|              |10.0.0 - 10.2.4    |                      |                   |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP DNS    |12.0.0 - 12.1.2    |13.0.0                |Management user    |
|              |                   |12.1.2 HF1            |interface          |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP Edge   |11.0.0 - 11.3.0    |None                  |Management user    |
|Gateway       |10.1.0 - 10.2.4    |                      |interface          |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP GTM    |11.0.0 - 11.6.1    |None                  |Management user    |
|              |10.0.0 - 10.2.4    |                      |interface          |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP Link   |12.0.0 - 12.1.2    |13.0.0                |Management user    |
|Controller    |11.0.0 - 11.6.1    |12.1.2 HF1            |interface          |
|              |10.0.0 - 10.2.4    |                      |                   |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP PEM    |12.0.0 - 12.1.2    |13.0.0                |Management user    |
|              |11.3.0 - 11.6.1    |12.1.2 HF1            |interface          |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP PSM    |11.0.0 - 11.4.1    |None                  |Management user    |
|              |10.0.0 - 10.2.4    |                      |interface          |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP        |11.0.0 - 11.3.0    |None                  |Management user    |
|WebAccelerator|10.0.0 - 10.2.4    |                      |interface          |
+--------------+-------------------+----------------------+-------------------+
|BIG-IP WOM    |11.0.0 - 11.3.0    |None                  |Management user    |
|              |10.0.0 - 10.2.4    |                      |interface          |
+--------------+-------------------+----------------------+-------------------+
|ARX           |6.0.0 - 6.4.0      |None                  |Management user    |
|              |5.0.0 - 5.3.1      |                      |interface          |
+--------------+-------------------+----------------------+-------------------+
|Enterprise    |3.0.0 - 3.1.1      |None                  |Management user    |
|Manager       |2.0.0 - 2.3.0      |                      |interface          |
+--------------+-------------------+----------------------+-------------------+
|              |                   |                      |Administrative     |
|FirePass      |7.0.0              |None                  |Console            |
|              |6.0.0 - 6.1.0      |                      |User-facing web    |
|              |                   |                      |resources          |
+--------------+-------------------+----------------------+-------------------+

Security Advisory Recommended Actions

If the previous table lists a version in the Versions known to be not
vulnerable column, you can eliminate this vulnerability by upgrading to the
listed version. If the listed version is older than the version you are
currently running, or if the table does not list any version in the column,
then no upgrade candidate currently exists.

Mitigation

BIG-IP

To mitigate this vulnerability, you should permit management access to F5
products only over a secure network and restrict command line access for
affected systems to trusted users. For more information, refer to K13309:
Restricting access to the Configuration utility by source IP address (11.x -
14.x) and K13092: Overview of securing access to the BIG-IP system.

FirePass

To mitigate this issue, refer to K12635: Mitigating Slowloris DoS against a
FirePass device.

Supplemental Information

  o K10260: Mitigating Slowloris DoS attacks with the BIG-IP system
  o K9970: Subscribing to email notifications regarding F5 products
  o K9957: Creating a custom RSS feed to view new and updated documents
  o K4602: Overview of the F5 security vulnerability response policy
  o K4918: Overview of the F5 critical issue hotfix policy
  o K13123: Managing BIG-IP product hotfixes (11.x - 13.x)

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