2016-001: Desk.com is affected by Reflected Cross-Site Scripting vulnerability

Original release date: February 16, 2016
Last revised: February 16, 2016
Discovered by: José Antonio Pérez Piedra
Severity: 6.1/10 (CVSSv3 Base Metrics)

BACKGROUND

Desk(.)com is a help desk solution which allows companies to handle both traditional 1-to-1 communications as well as monitor and respond to social media. It also provides email support system and knowledgebase.

DESCRIPTION

Desk(.)com is affected by Reflected Cross-Site Scripting vulnerability in the email contact form. The vulnerable resource does not properly check the type of the parameters passed to the application through GET requests. It allows malicious users to bypass the sanitizer and execute arbitrary HTML/script code in the context of the victim's browser.

PROOF OF CONCEPT

The affected resource is:

    /customer/portal/emails/new
	
    All GET parameters are affected by this vulnerability, for example:
    email[body]
    email[subject]
    interaction[email]
    interaction[name]

The application does not filter the parameters if they are passed as nested arrays and reflects its content in the response. Here is a PoC:

		
⁄customer⁄portal⁄emails⁄new?email[body]=&email[subject][]=asd'>
	<img onerror="prompt(1)" src="x" ⁄>&interaction[email]=&interaction[name]=

BUSINESS IMPACT

An attacker can execute arbitrary HTML or script code in a targeted user's browser, this can leverage to steal sensitive information as user credentials, personal data, etc.

SYSTEMS AFFECTED

www.desk.com

SOLUTION

This vulnerability have been corrected.

REVISION HISTORY

February 16, 2016: Initial release

DISCLOSURE TIMELINE

  • November 4, 2015: Vulnerability acquired by Internet Security Auditors.
  • November 6, 2015 Contact with Desk.com Security Team.
  • December 1, 2015: Internet Security Auditors confirm that the bug have bveen corrected.
  • February 16, 2016: Advisory published.

REFERENCES

LEGAL NOTICES

The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise. Internet Security Auditors accepts no responsibility for any damage caused by the use or misuse of this information.

ABOUT

Internet Security Auditors is a Spain and Colombia based company leader in web application testing, network security, penetration testing, security compliance implementation and assessing. Our clients include some of the largest companies in areas such as finance, telecommunications, insurance, ITC, etc. We are vendor independent provider with a deep expertise since 2001. Our efforts in R&D include vulnerability research, open security project collaboration and whitepapers, presentations and security events participation and promotion. For further information regarding our security services, contact us.