MyBB 1.8.6 Profile Editor Upload/modcp.php cross site scripting

Summaryinfo

A vulnerability described as problematic has been identified in MyBB 1.8.6. Impacted is an unknown function of the file Upload/modcp.php of the component Profile Editor. Such manipulation leads to cross site scripting. It is possible to launch the attack remotely. Furthermore, an exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in MyBB 1.8.6 (Content Management System) and classified as problematic. Affected by this issue is an unknown code block of the file Upload/modcp.php of the component Profile Editor. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-80. The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages. Impacted is integrity.

The weakness was published 11/10/2016 by Tim Coen with Curesec Research Team as MyBB 1.8.6: XSS as not defined mailinglist post (Full-Disclosure). The advisory is shared for download at seclists.org. The public release has been coordinated with the vendor. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. Technical details as well as a public exploit are known. The MITRE ATT&CK project declares the attack technique as T1059.007. The advisory points out:

The profile editor of the moderator control panel does not properly encode the signature of a user when editing it. Because of this, a user can create a specifically crafted signature and - once a moderator or admin visits the profile editor for that user - the injected code will be executed in the context of the victims browser.

A public exploit has been developed by Tim Coen and been published immediately after the advisory. The exploit is available at seclists.org. It is declared as proof-of-concept. The vulnerability was handled as a non-public zero-day exploit for at least 279 days. During that time the estimated underground price was around $5k-$25k. By approaching the search of inurl:Upload/modcp.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 1.8.7 eliminates this vulnerability. The upgrade is hosted for download at resources.mybb.com. A possible mitigation has been published before and not just after the disclosure of the vulnerability.

Similar entries are available at VDB-93561, VDB-93562, VDB-93563 and VDB-93564. VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Content Management System

Name

• MyBB

Version

• 1.8.6

License

• open-source

Website

• Product: https://mybb.com/

CPE 2.3info

• 🔍

CPE 2.2info

• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion