The ApiBase::getWatchlistUser function in MediaWiki before 1.23.10, 1.24.x before 1.24.3, and 1.25.x before 1.25.2 does not perform token comparison in constant time, which allows remote attackers to guess the watchlist token and bypass CSRF protection via a timing attack.

The version of MediaWiki installed is 1.23.x earlier than 1.23.10, 1.24.x earlier than 1.24.3, or 1.25.x earlier than 1.25.2. Therefore, it is affected by multiple vulnerabilities :

 - A flaw exists due to 'Special:DeletedContributions' failing to properly protect the IP of autoblocked users. This may allow attackers to gain access to IP address information. (CVE-2015-6727)
 - A flaw exists as HTTP requests do not require multiple steps, explicit confirmation, or a unique token when performing certain sensitive actions. By tricking a user into following a specially crafted link, a context-dependent attacker can perform a Cross-Site Request Forgery (CSRF / XSRF) attack causing the victim to modify a user's watchlist. (CVE-2015-6728)
 - A flaw allows a reflected cross-site scripting (XSS) attack. This flaw exists because the 'thumb.php' script does not validate input to error messages before returning it to users. This may allow a context-dependent attacker to create a specially crafted request that would execute arbitrary script code in a user's browser session within the trust relationship between their browser and the server. (CVE-2015-6729, 2015-6730)

The remote host is affected by the vulnerability described in GLSA-201510-05 (MediaWiki: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in MediaWiki. Please       review the CVE identifiers referenced below for details.
  Impact :

    A remote attacker may be able to create a Denial of Service condition,       obtain sensitive information, bypass security restrictions, and inject       arbitrary web script or HTML.
  Workaround :

    There is no known workaround at this time.

- (T94116) SECURITY: Compare API watchlist token in     constant time * (T97391) SECURITY: Escape error message     strings in thumb.php * (T106893) SECURITY: Don't leak     autoblocked IP addresses on Special:DeletedContributions
    * (T102562) Fix InstantCommons parameters to handle the     new HTTPS-only policy of Wikimedia Commons. * (T100767)     Setting a configuration setting for skin or extension to     false in LocalSettings.php was not working. * (T100635)     API action=opensearch json output no longer breaks when     $wgDebugToolbar is enabled. * (T102522) Using an     extension.json or skin.json file which has a     'manifest_version' property for 1.26 compatability will     no longer trigger warnings. * (T86156) Running     updateSearchIndex.php will not throw an error as     page_restrictions has been added to the locked table     list. * Special:Version would throw notices if using SVN     due to an incorrectly named variable. Add an additional     check that an index is defined.

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

MediaWiki reports :

Internal review discovered that Special:DeletedContributions did not properly protect the IP of autoblocked users. This fix makes the functionality of Special:DeletedContributions consistent with Special:Contributions and Special:BlockList.

Internal review discovered that watchlist anti-csrf tokens were not being compared in constant time, which could allow various timing attacks. This could allow an attacker to modify a user's watchlist via csrf

John Menerick reported that MediaWiki's thumb.php failed to sanitize various error messages, resulting in xss.

ID	Name	Product	Family	Severity
9470	MediaWiki < 1.23.10 / 1.24.3 / 1.25.2 Multiple Vulnerabilities	Nessus Network Monitor	CGI	low
86690	GLSA-201510-05 : MediaWiki: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	high
85698	Fedora 23 : mediawiki-1.25.2-2.fc23 (2015-13920)	Nessus	Fedora Local Security Checks	high
85428	FreeBSD : mediawiki -- multiple vulnerabilities (6241b5df-42a1-11e5-93ad-002590263bf5)	Nessus	FreeBSD Local Security Checks	high

Detections

Analytics

CVE-2015-6728

high

Tenable Plugins

low

high

high

high