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Update Protection against Exim MTA string_format Remote Code Execution Vulnerability

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Check Point Reference: CPAI-2010-348
Date Published:
Severity:
Source: Secunia Advisory: SA40019
Industry Reference(s): CVE-2010-4344
Protection Provided by: Security Gateway
  • R71
  • R70
IPS-1
  • IPS-1
  • IPS-1 NGX R65
Who is Vulnerable?
Exim.org Exim4 4.69 and prior
Vulnerability Description
A heap buffer overflow vulnerability has been reported in Exim Mail Transfer Agent (MTA). The Exim mail server is a full featured mail transfer agent (MTA) used in Unix-like platforms. It contains implementations of SMTP server for incoming messages as well as an SMTP or LMTP client for outgoing email. A remote attacker may exploit this vulnerability to execute arbitrary code on a vulnerable system.
Update/Patch Available
Apply patches:
Exim-Dev 
Vulnerability Details
The vulnerability is due to a buffer overflow in the Exim MTA that fails to properly handle malformed email headers. A remote attacker may exploit this issue to execute arbitrary code on an Exim server by sending a specially crafted email to the vulnerable server. Successful exploitation of this vulnerability would allow the attacker to execute code within the security context of the affected server.

Protection Overview
This protection detects and blocks malformed emaila sent to the vulnerable server. 

In order for the protection to be activated, update your Security Gateway product to the latest IPS update. For information on how to update IPS, go to SBP-2006-05, Protection taband select the version of your choice.

To configure the defense, select your product from the list below and follow the related protection steps.

Security Gateway: R70/R71

How Can I Protect My Network?
1. In the IPS tab, click Protections > By Protocol > Application Intelligence > Mail > SMTP.
2. In the right pane, double-click the following protection:

Exim MTA string_format Remote Code Execution

3. In the Protection Details window, click on Edit. Choose the protection's Action (Override IPS Policy with: Prevent/Detect), and apply Additional Settings. 
4. Install policy on all modules. 

How Do I Know if My Network is Under Attack?
SmartView Tracker will log the following entries:

Attack Name: SMTP Policy Violation 
Attack Information: Exim MTA string_format remote code execution

IPS-1 & IPS-1 NGX R65

How Can I Protect My Network?
1. In the IPS-1 Policy Manager, click on the Protection tab.
2. In the Protection tree, click Application Intelligence > SMTP2, and select the Long Lines protection group.
3. Click Long mail header (IPS-1 NGX R65 only).
4. In the configuration pane, under Settings, check Active.
5. Click on Install Policy.

 

How Do I Know if My Network is Under Attack?
Upon attack, the following entries will be logged:

Alert Name: SMTP Long Lines
Description: Long mail header