Vulnerability identifier: #VU2795

Vulnerability risk: High

CVSSv3.1: 9.2 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2009-3023

CWE-ID: CWE-121

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Microsoft IIS
Server applications / Web servers

Vendor: Microsoft

Description
The vulnerability allows a remote authenticated attacker to execute arbitrary code on the target system.

The weakness exists due to stack-based buffer overflow in FTP server. A remote authenticated attacker can send a specially crafted FTP NLST command containing a wildcard that references a subdirectory, trigger memory corruption and execute arbitrary code on the system with privileges of the current user.

Successful exploitation of the vulnerability results in arbitrary code execution on the vulnerable system.

Note: the vulnerability was being actively exploited.

Mitigation
Install update from vendor's website:

Microsoft Internet Information Services 5.0 on
Microsoft Windows 2000 Service Pack 4:
https://www.microsoft.com/downloads/details.aspx?familyid=7fecd367-aaff-458b-91bc-8925c8e57528
Microsoft Internet Information Services 5.1 on
Windows XP Service Pack 2 and Windows XP Service Pack 3:
https://www.microsoft.com/downloads/details.aspx?familyid=2ae0bdd4-f8b2-420a-b1ac-d2cdaa87c828
Microsoft Internet Information Services 6.0 on
Windows XP Professional x64 Edition Service Pack 2:
https://www.microsoft.com/downloads/details.aspx?familyid=819dd2d1-cad5-4784-9baf-185d8a76df5d
Microsoft Internet Information Services 6.0 on
Windows Server 2003 Service Pack 2:
https://www.microsoft.com/downloads/details.aspx?familyid=48256ea3-b433-4e84-9019-22300069cfc1
Microsoft Internet Information Services 6.0 on
Windows Server 2003 x64 Edition Service Pack 2:
https://www.microsoft.com/downloads/details.aspx?familyid=61bded07-201e-4815-ac1e-468bf907e063
Microsoft Internet Information Services 6.0 on
Windows Server 2003 with SP2 for Itanium-based Systems:
https://www.microsoft.com/downloads/details.aspx?familyid=b99d4d9b-e0cc-4a8c-ad99-6a53958b37c8

Vulnerable software versions

Microsoft IIS: 5.0 - 6.0

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External links
http://technet.microsoft.com/en-us/library/security/ms09-053.aspx

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.