Vulnerability Note VU#210148

wget contains directory traversal vulnerability

Original Release date: 10 Dec 2002 | Last revised: 14 Apr 2003

Overview

The wget utility contains directory traversal vulnerabilities that allow a malicious FTP server to overwrite files on the client host.

Description

In a typical file transfer operation, one participant (the client) requests a file while a second participant (the server) provides the requested file. Before processing each request, many server implementations will consult an access control policy to determine whether the client should be permitted to read, write, or create a file at the requested location. If the client is able to craft a request that violates the server's access control policy, then the server contains a vulnerability. Since most vulnerabilities of this type involve escaping a restricted set of directories, they are commonly known as "directory traversal" vulnerabilities.

Directory traversal vulnerabilities are most often reported in server implementations, but recent research into the behavior of FTP clients has revealed vulnerabilities in several file transfer applications, including the wget utility. To exploit these vulnerabilities, an attacker must convince the victim user to access a specific FTP server containing files with crafted filenames. When an affected version of wget attempts to download one of these files, the crafted filename causes the utility to write the downloaded files to the location specified by the filename, not by the victim user. In some cases, the attacker must use a modified FTP server to allow the crafted filenames to be passed to the client.

For more detailed information regarding this research, please read "Directory Traversal Vulnerabilities in FTP Clients", written by Steve Christey.

Impact

This vulnerability allows an attacker to mislead wget users, convincing them to unintentionally create or overwrite files on the client's filesystem.

Solution

Apply a patch from your vendor

For vendor-specific information regarding vulnerability status and patch availability, please consult the Systems Affected section of this document

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
ConectivaAffected05 Dec 200213 Dec 2002
DebianAffected05 Dec 200213 Dec 2002
Gentoo LinuxAffected20 Dec 200231 Dec 2002
MandrakeSoftAffected05 Dec 200212 Dec 2002
Red Hat Inc.Affected05 Dec 200210 Dec 2002
TrustixAffected19 Dec 200231 Dec 2002
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A

References

Credit

The CERT/CC thanks Steve Christey for his discovery and analysis of this vulnerability.

This document was written by Jeffrey P. Lanza.

Other Information

  • CVE IDs: CAN-2002-1344
  • Date Public: 10 Dec 2002
  • Date First Published: 10 Dec 2002
  • Date Last Updated: 14 Apr 2003
  • Severity Metric: 0.68
  • Document Revision: 12

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