======================================================================== = Multiple vulnerabilities within RockLiffe MailSite Express WebMail = Also available online at http://www.security-assessment.com/Advisories/Rockliffe_Express_Webmail_Vuln erabilities.pdf = Vendor Website: = http://www.rockliffe.com = Affected Version: = All versions of RockLiffe MailSite Express WebMail prior v6.1.22 = = Public disclosure on October 28th, 2005 ======================================================================== == Overview == During an audit of a client, Security-Assessment.com discovered multiple critical vulnerabilities within the RockLiffe MailSite Express WebMail software. The vulnerabilities include the retrieval of arbitrary files from the web server, and bypassing attachment validation routines allowing for remote code execution. == Exploitation == Exploit 1: Cross Site Scripting Vulnerabilities ------------------------------------------------------------------------ Recipients who save their login information locally are vulnerable to account theft when viewing HTML encoded messages with embedded JavaScript. When the option to save login information is selected the users password is stored as plaintext within the cookie. Crafting an email with scripting in the body will cause the execution of the scripting in the context of the site, allowing for the theft of the stored credentials. A basic test for this is to include the following in the body of a message; <script> alert(document.cookie) </script> Exploit 2: Multiple Script Attachment Validation Flaws ------------------------------------------------------------------------ The WebMail software attempts to verify the validity of an attachment within a received message. It automatically modifies the extension of any files ending in .asp, by changing them to .asp.txt. This is an attempt to avoid remote code execution through an attached file. However, these validity checks can be defeated and script files saved to the server. By default, only files ending in .asp are identified and rejected as script files. If a malicious user were to attach an .asa file instead, Web Mail would accept the script attachment, saving the file locally with the .asa extension. When the .asa file is requested the script contents are executed in the same manner as a .asp file. This flaw could also be affected by other extensions such as .htr and .aspx. A similar flaw exists when an attachment is sent with the filename unknown.unk. In this instance the message subject is used as the file name, and .asa script files can be saved locally. Exploit 3: Retrieve Arbitrary System Files via Web Mail ------------------------------------------------------------------------ The location of file attachments for a mail message currently been composed, are stored as a physical file path included in the HTML as a hidden field. An example of this is shown below; <input type="hidden" name="AttachPath" value="H:\Express3Webmail6.1.20\cache\5116FC5113B47C0B1CDD5\440820634> This value points to the location where the attachments for the message are stored, by default all files within this directory are considered attachments for the message currently being composed. This value can be manipulated and a message can be sent with arbitrary 'attachments'. For example, posting the variable AttachPath = H:\Express3Webmail6.1.20\ would send the recipient a copy of the docroot. == Solutions == Security-Assessment.com has been in contact with RockLiffe software and a new version of the software has been released to address the discovered vulnerabilities. Security-Assessment.com urges RockLiffe users to upgrade to v6.1.22 by downloading the new version at http://www.rockliffe.com/userroom/download.asp == Credit == Discovered and advised to RockLiffe software July, 2005 by Paul Craig of Security-Assessment.com == About Security-Assessment.com == Security-Assessment.com is a leader in intrusion testing and security code review, and leads the world with SA-ISO, online ISO17799 compliance management solution. Security-Assessment.com is committed to security research and development, and its team have previously identified a number of vulnerabilities in public and private software vendors products.