SCG D BIGIP

Summary

The BIG-IP family of products offers the application intelligence network managers need to ensure applications are fast, secure and available. All BIG-IP products share a common underlying architecture, F5's Traffic Management Operating System (TMOS), which provides unified intelligence, flexibility and programmability. Together, BIG-IP's powerful platforms, advanced modules, and centralized management system make up the most comprehensive set of application delivery tools in the industry.

BIG-IP devices work on a modular system, which enables to add new functions as necessary to quickly adapt to changing application and business needs. The following modules are currently available for the BIG-IP system:

• Application Acceleration Manager (AAM)
• Advanced Firewall Manager (AFM)
• Access Policy Manager (APM)
• Application Security Manger (ASM)
• Global Traffic Manager (GTM)
• Link Controller (LC)
• Local Traffic Manager (LTM)
• Protocol Security Module (PSM)

Common Misconfigurations

BIG-IP persistence cookie information leakage

Description

An attacker can decode BIG-IP persistence cookie and receive sensitive information about internal network.

// Detailed description of the impact. Is it enabled by default? Vulnerable versions.

To implement persistence sessions BIG-IP system inserts a cookie into the HTTP response, which well-behaved clients include in subsequent HTTP requests for the host name until the cookie expires. The cookie, by default, is named BIGipServer<pool_name>. The cookie is set to expire based on the time-out configured in the persistence profile. The cookie value contains the encoded IP address and port of the destination server [1] in the following format: BIGipServer<pool name> = <coded server IP>.<coded server port>.0000

After decoding [2] this value an attacker receives an internal IP address and port number of backend servers. In some cases an attacker can also retreive sensitive informaion via <pool_name> value in the cookie name. For example, if an administrator give meaningful name to server pool (e.g. Sharepoint, 10.1.1.0, AD_prod) an attacker will get some additional information about network.

How to test

1. Run intercepting proxy or traffic intercepting browser plug-in, trap all responses where a cookie is set by the web application.
2. Log in to web application behing BIG-IP and inspect cookies.
3. Find a cookie with name beginning with BIGipServer string or with value which has format as <coded server IP>.<coded server port>.0000 (e.g. 1677787402.36895.0000).
4. Try to decode this value using available tools (e.g. WhiteHat Security Big IP Cookie Decoder).
5. Inspect suffix of BIGipServer cookie name and verify that it does not contain any sensitive information about network infrustructure.

EXAMPLE 1

This example shows a GET request to BIG-IP with LTM module and response containing BIGipServer cookie.

GET https://x.x.x.x/ HTTP/1.1
Host: x.x.x.x

Result Expected:

HTTP/1.1 200 OK
Set-Cookie: BIGipServerOldOWA=110536896.20480.0000; path=/

Here we can see that pool has the meaningful name OldOWA and get the following destination server address:

• IP Address = 192.168.150.6
• Port = 80.

// Proof-of-concept here. Please include the screenshots and widely known tools/scanners!

Remediation

Initial/common value of parameter "listUsers" from config.xml is set to "true".

To assess the vulnerability it is enough to change the value to false:

<security>
	<listUsers>false</listUsers>
</security>

Misconfiguration 2

...

References

• F5 Networks Official Site
• BIG-IP Modules Datasheet