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Update Protection against Microsoft Internet Information Services FTP Server Recursive Listing Denial of Service Vulnerability (MS09-053)

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Check Point Reference: CPAI-2009-183
Date Published:
Severity:
Last Updated:
Source: Microsoft Security Advisory (975191)
Microsoft Security Bulletin MS09-053
Industry Reference(s): CVE-2009-2521
Protection Provided by: Security Gateway
  • R70
VPN-1
  • NGX R65
VSX
  • NGX R65
InterSpect
  • NGX
IPS-1
  • IPS-1
  • IPS-1 NGX R65
Who is Vulnerable?
Microsoft Internet Information Services 5.0
Microsoft Internet Information Services 5.1
Microsoft Internet Information Services 6.0
Microsoft Internet Information Services 7.0
Vulnerability Description
A stack consumption vulnerability has been discovered in Microsoft Internet Information Services (IIS) FTP server. IIS is a collection of Internet services packaged with several versions of the Windows operating system. IIS includes an FTP server service for exchanging and manipulating files over a TCP computer network. A remote attacker could use this issue to create a denial of service condition, thus crashing the vulnerable service.
Update/Patch Available
Apply patches:
Microsoft Security Bulletin MS09-053
Vulnerability Details
The vulnerability is due to resource exhaustion encountered when processing certain recursive directory listings. A remote attacker may exploit this issue by crafting an FTP command and sending it to a target server. Successful exploitation of this vulnerability would allow the attacker to crash the vulnerable service via a malicious command.

Protection Overview
This protection will detect and block attempts to exploit this vulnerability via malicious FTP patterns.

In order for the protection to be activated, update your Security Gateway/VPN-1/InterSpect product to the latest IPS/SmartDefense update. For information on how to update IPS/SmartDefense, go to SBP-2006-05, Protection tab and 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

How Can I Protect My Network?
1. In the IPS tab, click Protections > By Protocol > Application Intelligence > FTP.
2. In the right pane, double-click the Microsoft IIS FTP Server Recursive Listing Denial of Service protection.
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: FTP Enforcement Violation
Attack Information: Microsoft IIS FTP server recursive listing denial of service

VPN-1 NGX R65

How Can I Protect My Network?
1. In the SmartDefense tab, click Application Intelligence > FTP > Microsoft IIS FTP Server Recursive Listing Denial of Service.
2. In the configuration pane, under Settings > Mode, check Active.
3. Install policy on all modules.

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

Attack Name: FTP Enforcement Violation
Attack Information: Microsoft IIS FTP server recursive listing denial of service

VPN-1 VSX NGX R65

How Can I Protect My Network?
1. In the SmartDefense tab, click Application Intelligence > FTP > Microsoft IIS FTP Server Recursive Listing Denial of Service.
2. In the configuration pane, under Settings > Mode, check Active.
3. Install policy on all modules.

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

Attack Name: FTP Enforcement Violation
Attack Information: Microsoft IIS FTP server recursive listing denial of service

InterSpect NGX

How Can I Protect My Network?
1. In the left pane, select Profiles > Default Protection and select the SmartDefense page of the profile.
2. In the SmartDefense tree, click Application Intelligence > FTP.
2. Select the following:

Microsoft IIS FTP Server Recursive Listing Denial of Service

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: FTP Enforcement Violation
Attack Information: Microsoft IIS FTP server recursive listing denial of service

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 > FTP, and select the FTP Command Attacks protection group.
3. Click FTP command requesting filesystem recursion and Long FTP pathname (IPS-1 NGX R65 only).
4. In the configuration pane, under Settings, check Active.
5. Click on Install Policy.

By enabling the Long FTP patname protection, IPS-1 will detect and block FTP commands with paths that exceed a configurable threshold. To configure this threshold. The default value for this is 250 bytes. To configure a new value:

1. After you have enabled the Long FTP pathname protection, in the configuration pane, enter a value for 'Maximum length of the full pathname'.
2. Click on Install Policy.

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

Alert Name: FTP Commands
Description: FTP command requesting filesystem recursion

Alert Name: FTP Commands
Description: Long FTP pathname