Vendor Description
“ServiceDesk Plus is a game changer in turning IT teams from daily fire-fighting to delivering awesome customer service. It provides great visibility and central control in dealing with IT issues to ensure that businesses suffer no downtime. For 10 years and running, it has been delivering smiles to millions of IT folks, end users, and stakeholders alike.”
Source: https://www.manageengine.com/products/service-desk
Business Recommendation
The vendor provides a patched version and it should be installed immediately. Furthermore, a thorough security analysis is highly recommended as only a short spot check has been performed and further critical issues are to be expected. A workaround exists for mitigating vulnerability 1b (user enumeration).
Vulnerability Overview/ Description
1) Unauthenticated sensitive information leakage
A) UNAUTHENTICATED SENSITIVE INFORMATION LEAKAGE
The software offers functionality (fosagent) that an unauthenticated attacker can exploit in order to gain information of internal “events”. In our test it was possible to access sensitive internal information (tickets) written by users of this application in exchange with the support team. Depending on the contents of the tickets, sensitive data might leak through this functionality. It is likely, that it also depends on the configuration of ServiceDesk Plus which information is stored in those “events”.
B) USER ENUMERATION IN AJAXDOMAINSERVLET (CVE-2019-15045)
It is possible to collect valid usernames by interacting with the “AjaxDomainServlet” function of the application without prior authentication. This vulnerability is useful to increase the efficiency of brute force attacks. If the username is known, it is easier to find the corresponding password.
Furthermore, the servlet leaks information, whether the user is a locally configured or a domain user and it also leaks the internal domain names of the requested user account.
According to the vendor, the affected feature is intended behaviour and a workaround in order to disable it has been provided (see further below).
Proof Of Concept
1) Unauthenticated sensitive information leakage
A) UNAUTHENTICATED DOWNLOAD OF INTERNAL SUPPORT TICKET INFORMATION (CVE-2019-15046)
The “fosagent” functionality provides a “download-file” servlet which an unauthenticated attacker can use in order to iterate through existing internal “events”. The information that can be downloaded looks like internal ticket system information and other data exchanged between users and the help desk support team. It is necessary to supply the “log-pos” parameter given a number followed by a colon character and another number to access the corresponding event index. An attacker can just increment those numbers and access different information.
$IP/fosagent/repl/download-file
B) USER ENUMERATION IN AJAXDOMAINSERVLET (CVE-2019-15045)
The following URL can be used to efficiently enumerate user accounts configured within ManageEngine ServiceDesk Plus. No prior authentication is required for this functionality. The “search” parameter is used for supplying the user account name.
$IP/domainServlet/AJaxDomainServlet
If the user exists and is a local user (configured within the web application) it will show “Not in Domain” as a result. If the user exists and is a domain user (e.g. LDAP) it will show the corresponding internal domain name as a result. If the page stays empty the user does not exist.
Vulnerable / Tested Versions:
Version 10 has been tested. The vendor did not confirm whether older releases are affected as well.