wget 1.8.x and 1.9.x allows a remote malicious web server to overwrite certain files via a redirection URL containing a ".." that resolves to the IP address of the malicious server, which bypasses wget's filtering for ".." sequences.

Updated wget package that fixes several security issues is now available.

This update has been rated as having low security impact by the Red Hat Security Response Team.

GNU Wget is a file retrieval utility that can use either the HTTP or FTP protocols.

A bug was found in the way wget writes files to the local disk. If a malicious local user has write access to the directory wget is saving a file into, it is possible to overwrite files that the user running wget has write access to. (CVE-2004-2014)

A bug was found in the way wget filters redirection URLs. It is possible for a malicious Web server to overwrite files the user running wget has write access to. Note: in order for this attack to succeed the local DNS would need to resolve '..' to an IP address, which is an unlikely situation. (CVE-2004-1487)

A bug was found in the way wget displays HTTP response codes. It is possible that a malicious web server could inject a specially crafted terminal escape sequence capable of misleading the user running wget.
(CVE-2004-1488)

Users should upgrade to this updated package, which contains a version of wget that is not vulnerable to these issues.

Jan Minar discovered a path traversal vulnerability in wget. If the name '..' was a valid host name (which can be achieved with a malicious or poisoned domain name server), it was possible to trick wget into creating downloaded files into arbitrary locations with arbitrary names. For example, wget could silently overwrite the users ~/.bashrc and other configuration files which are executed automatically. (CAN-2004-1487)

Jan Minar also discovered that wget printed HTTP response strings from the server to the terminal without any filtering. Malicious HTTP servers could exploit this to send arbitrary terminal sequences and strings which would then be executed and printed to the console. This could potentially lead to arbitrary code execution with the privileges of the user invoking wget. (CAN-2004-1488)

Hugo Vazquez Carames discovered a race condition when writing output files. After wget determined the output file name, but before the file was actually opened (the time window is determined by the delay of the first received data packet), a local attacker with with write permission to the download directory could create a symbolic link with the name of the output file. This could be exploited to overwrite arbitrary files with the permissions of the user invoking wget.
(CAN-2004-2014).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

The remote Redhat Enterprise Linux 4 host has a package installed that is affected by multiple vulnerabilities as referenced in the RHSA-2005:771 advisory.

    GNU Wget is a file retrieval utility that can use either the HTTP or     FTP protocols.

    A bug was found in the way wget writes files to the local disk. If a     malicious local user has write access to the directory wget is saving a     file into, it is possible to overwrite files that the user running wget     has write access to. (CAN-2004-2014)

    A bug was found in the way wget filters redirection URLs. It is possible     for a malicious Web server to overwrite files the user running wget has     write access to. Note: in order for this attack to succeed the local     DNS would need to resolve .. to an IP address, which is an unlikely     situation.  (CAN-2004-1487)

    A bug was found in the way wget displays HTTP response codes. It is     possible that a malicious web server could inject a specially crafted     terminal escape sequence capable of misleading the user running wget.
    (CAN-2004-1488)

    Users should upgrade to this updated package, which contains a version of     wget that is not vulnerable to these issues.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Jan Minar reports that there exists multiple vulnerabilities in wget :

Wget erroneously thinks that the current directory is a fair game, and will happily write in any file in and below it. Malicious HTTP response or malicious HTML file can redirect wget to a file that is vital to the system, and wget will create/append/overwrite it.

Wget apparently has at least two methods of ``sanitizing'' the potentially malicious data it receives from the HTTP stream, therefore a malicious redirects can pass the check. We haven't find a way to trick wget into writing above the parent directory, which doesn't mean it's not possible.

Malicious HTTP response can overwrite parts of the terminal so that the user will not notice anything wrong, or will believe the error was not fatal.

Two vulnerabilities were found in wget. The first is that an HTTP redirect statement could be used to do a directory traversal and write to files outside of the current directory. The second is that HTTP redirect statements could be used to overwrite dot ('.') files, potentially overwriting the user's configuration files (such as .bashrc, etc.).

The updated packages have been patched to help address these problems by replacing dangerous directories and filenames containing the dot ('.') character with an underscore ('_') character.

The remote host is using a version of wget that contains bugs that may allow a malicious to server to overwrite or inject data in files or perform a directory traversal. 

ID	Name	Product	Family	Type	Severity
21857	CentOS 3 / 4 : wget (CESA-2005:771)	Nessus	CentOS Local Security Checks	Local	medium
20538	Ubuntu 4.10 / 5.04 : wget vulnerabilities (USN-145-1)	Nessus	Ubuntu Local Security Checks	Local	medium
19833	RHEL 4 : wget (RHSA-2005:771)	Nessus	Red Hat Local Security Checks	Local	critical
18831	FreeBSD : wget -- multiple vulnerabilities (06f142ff-4df3-11d9-a9e7-0001020eed82)	Nessus	FreeBSD Local Security Checks	Local	medium
18440	Mandrake Linux Security Advisory : wget (MDKSA-2005:098)	Nessus	Mandriva Local Security Checks	Local	medium
2449	GNU WGet Multiple Remote Vulnerabilities	Nessus Network Monitor	Web Clients		medium

Detections

Analytics

CVE-2004-1487

critical

Tenable Plugins

medium

medium

critical

medium

medium

medium