Core Security Technologies - Corelabs Advisory
ZOHO ManageEngine ADSelfService multiple vulnerabilities
Title: ZOHO ManageEngine ADSelfService multiple vulnerabilities
Advisory ID: CORE-2011-0103
Advisory URL: http://www.coresecurity.com/content/zoho-manageengine-vulnerabilities
Date published: 2011-02-10
Date of last update: 2011-02-10
Vendors contacted: ZOHO Corporation
Release mode: Coordinated release
Class: Protection Mechanism Failure [CWE-693], Authentication Issues [CWE-287], Cross-Site Scripting (XSS) [CWE-79]
Impact: Code execution, Security bypass
Remotely Exploitable: Yes
Locally Exploitable: No
CVE Name: CVE-2010-3272, CVE-2010-3273, CVE-2010-3274
ManageEngine ADSelfService Plus  is a secure, web-based, end-user password reset management program. This software helps domain users to perform self service password reset, self service account unlock and employee self update of personal details (e.g. telephone numbers, etc) in Microsoft Windows Active Directory. Administrators find it easy to automate password resets, account unlocks while managing optimizing the expenses associated with helpdesk calls.
The security question mechanism used for password recovery can be weakened by tampering the HTTP POST request containing the answers, allowing an attacker to pass the security check by guessing just one of the security answers. Additionally, the CAPTCHA mechanism can be bypassed in the same manner, enabling the automation of the guessing attempts.
The security question mechanism can also be bypassed by changing the flow of the application, skipping the security question mechanism and sending a HTTP request requiring the password change immediately after declaring which user is to run the recovery procedure.
Additionally, two cross site scripting vulnerabilities were found related to search functions.
Core would like to thanks Manikandan.T  for giving us the following detailed information about the way Zoho team has addressed the security vulnerabilities highlighted in this document.
[CVE-2010-3272] In addition to the Security Questions, the latest version of ADSelfService Plus also includes an SMS Verification / Email Verification mechanism. This adds an additional security while password. Users must confirm the code sent to their mobile phones / email when they are to reset password / unlock accounts.
The earlier Builds used URL based on Post Request which was considered vulnerable. This has been replaced by a more secure Tokenizer mechanism. This mechanism prevents "by-passing any process / steps involved in password reset / account unlock". The Tokenizer mechanism mandates the flow of addressing every process only in the defined sequence. This implies that the "Hide_Captcha / quesList" fields cannot be altered; if not, they do not follow the desired sequence.
[CVE-2010-3273] Earlier version of ADSelfService Plus checked the validation only at the page where the user was present. Now Each and Every step and also the previous steps are being validated. The "Tokenizer Method" ensures that no steps are bypassed. It also ensures that validation occurs at every level and also only in the sequence desired.
[CVE-2010-3274] Security Filters are used to prevent Cross Site Scripting vulnerabilities. ADSelfService Plus now checks every input provided by a user at all the pages including "Password Reset / Unlock Account", Employee Search pages.
This vulnerability was discovered and researched by Ernesto Álvarez from Core Security Technologies. The publication of this advisory was coordinated by Fernando Miranda from Core Security Advisories team.
[CVE-2010-3272] The procedure to recover a lost password involves the user answering a series of security questions set during enrollment. After the recovery request and user ID have been sent, the system requires the user to answer a certain number of security questions, whose answers are then sent using a POST request, as seen below.
POST /accounts/ValidateAnswers?methodToCall=validateAll HTTP/1.1 Host: SERVER User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:18.104.22.168) Gecko/20101206 Ubuntu/10.10 (maverick) Firefox/3.6.13 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip,deflate Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive: 115 Proxy-Connection: keep-alive Referer: <http://SERVER/accounts/ValidateUser> Cookie: JSESSIONID=8F93EB242EF06C51BE93EB0CEDA69085 Content-Type: application/x-www-form-urlencoded Content-Length: 294 loginId=1501&Hide_Captcha=0&POLICY_ID=1&Confirm_Answer=1&SESSION_EXPIRY_TIME=5&LOGIN_NAME=alice&REM_SESSION_TIME=00%3A40&bAns=11111&bQues=PreDefined-2&bAns=22222&bQues=PreDefined-3&bAns=33333&bQues=PreDefined-4&bAns=44444&bQues=PreDefined-5&quesList=4&DIGEST=qodpgd&next=Continue&DIS_ALL_QUES=1
As seen in the HTTP POST above, the client has the ability to decide:
Therefore, an attacker can choose to answer just one security question of his choice, and this procedure can be automated, since the captcha can be bypassed. The reason for this weakness is that most of the recovery logic is left to the client to execute. This allows the client to alter the recovery procedure, weakening the process.
8.2. Security question bypass
[CVE-2010-3273] The security question mechanism can also be completely bypassed, allowing an attacker to reset an arbitrary user password. In order to bypass the mechanism, an attacker must first select the user whose password is to be changed, an operation which does not require authentication, and then skip the security question mechanism, issuing a HTTP request to the URL that accept password changes.
The normal recovery procedure in the ADSelfService Plus system consists of four steps:
//SERVER/accounts/Reset, the user is prompted to enter his user id.
http://SERVER/accounts/ValidateUserusing a HTTP POST. During this step, the user id is associated with the HTTP session (as shown in the JSESSIONID cookie). The user is prompted with the security questions.
If the answers are correct, a HTTP page with a form to input the new password is sent to the user. If the answers are wrong, the user is prompted again for the correct answers, and the step 3 must be redone.
http://SERVER/accounts/ResetResult. The server resets the password.
While some of the logic (mostly requiring changes to server data) is on the server side, the order of the steps to be performed can be controlled by the user. By performing steps 2 and 4 while skipping step 3, the user is able to change the password for another user of his choice. This flaw is due to the way the server acts on the information received. Step 2 associates a JSESSIONID to a user id (apparently necessary to perform step 3) while step 4 changes the password of whatever account is associated with the JSP session, setting it to the value posted. Since the server does not check whether step 3 has been completed, forging the appropriate HTTP POST requests necessary to perform the two steps mentioned is sufficient to change a user's password.
8.3. Cross site scripting vulnerabilities
[CVE-2010-3274] Two cross site scripting vulnerabilities were discovered, both related to the employee search function publicly available in the application. The first one involves the function used for listing matching usernames according to search criteria previously entered by the user, found in
http://SERVER/EmployeeSearch.cc?actionId=showList. The server reflects the contents of the
searchString field back to the user. An example of such an injection would be:
This example would cause the following HTML to be presented to the user:
The second cross site scripting vulnerability is present in the search page at
http://SERVER/EmployeeSearch.cc?actionId=Search. This page accepts the search parameters and then creates a new form to be sent to
<script> var searchValue = 'alice'; alert('xss'); var a='a'; var paramName = 'name'; var searchType = 'contains'; </script>
The example above was caused by following a link to:
This reflection is not obvious at first sight, as the source code shown after the process is finished is the showList page source. This code can be easily viewed if captured on the wire using a proxy server, though.
Additionally, since invoking
http://SERVER/EmployeeSearch.cc?actionId=Search causes a redirection to
http://SERVER/EmployeeSearch.cc?actionId=showList, entering any data capable of triggering a vulnerability in the latter page can be introduced in the former with the same results.
It is important to note that since the cross site scripting vulnerabilities were detected while investigating the authentication bypass issues and were considered a secondary matter, the pages containing them were not thoroughly tested. This leaves the possibility of other similar cross site scripting vulnerabilities remaining undetected.
 ADSelfService Plus <http://www.manageengine.com/products/self-service-password>.
 Manikandan.T, Senior Program Manager, ManageEngine ADSelfService Plus.
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