Security Bulletin MS02-054: Unchecked Buffer in File Decompression Functions Could Lead to Code Execution (Q329048)

2002-10-03T00:00:00
ID SECURITYVULNS:DOC:3570
Type securityvulns
Reporter Securityvulns
Modified 2002-10-03T00:00:00

Description


Title: Unchecked Buffer in File Decompression Functions Could Lead to Code Execution (Q329048) Date: 02 October 2002 Software: Microsoft Windows 98 with Plus! Pack, Windows Me, or Windows XP Impact: Two vulnerabilities, the most serious of which could run code of attacker?s choice Max Risk: Moderate Bulletin: MS02-054

Microsoft encourages customers to review the Security Bulletin at: http://www.microsoft.com/technet/security/bulletin/MS02-054.asp.


Issue:

Zipped files (files having a .zip extension) provide a means to store information in a way that uses less space on a hard disk. This is accomplished by compressing the files that are put into in the zipped file. On Windows 98 with Plus! Pack, Windows Me and Windows XP, the Compressed Folders feature allows zipped files to be treated as folders. The Compressed Folders feature can be used to create, add files to, and extract files from zipped files.

Two vulnerabilities exist in the Compressed Folders function:

  • An unchecked buffer exists in the programs that handles the decompressing of files from a zipped file. A security vulnerability results because attempts to open a file with a specially malformed filename contained in a zipped file could possibly result in Windows Explorer failing, or in code of the attacker?s choice being run.
  • The decompression function could place a file in a directory that was not the same as, or a child of, the target directory specified by the user as where the decompressed zip files should be placed. This could allow an attacker to put a file in a known location on the users system, such as placing a program in a startup directory

Mitigating Factors:

  • The vulnerabilities could not be exploited without user intervention. The attacker would need to entice the user to receive, store, and open the zipped file provided by the attacker.
  • The vulnerabilities could not be exploited remotely. An attacker would need to lure a user into receiving the zipped file onto the user?s machine. Best practices suggest users not accept e-mail attachments from people who are not trusted, and not to download files from untrusted Internet sites.
  • On Windows 98 and Windows Me, the Compressed Folders feature is not installed by default. Users who had not installed this feature would not be vulnerable.

Risk Rating:

  • Internet systems: Low
  • Intranet systems: Low
  • Client systems: Moderate

Patch Availability:

  • A patch is available to fix this vulnerability. Please read the Security Bulletin at http://www.microsoft.com/technet/security/bulletin/ms02-054.asp for information on obtaining this patch.

Acknowledgment:

  • Joe Testa of Rapid7, Inc. (http://www.rapid7.com/) for reporting the Unchecked Buffer in Zipped File Handling vulnerability.
  • zen-parse for reporting the Incorrect Target Path for Zipped File Decompression vulnerability.

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