Skip to main content

TrendMicro ScanMail for Microsoft Exchange (SMEX) predictable session token - CVE-2015-3326

It's time for another advisory (CVE-2015-3326), a simple one, for a vulnerability which can be found quickly and trivially. For those of you who just want to give a glance at the post, I suggest to directly watch the picture which says it all!

The following vulnerability was discovered on TrendMicro SMEX (ScanMail for Microsoft Exchange) 10 SP2 but it affects other versions as well.

While surfing the SMEX web administrative interface using a web proxy, I have noticed something in the HTTP request - the session token itself and its format, a number.

After observing a significant number of logins, the session token was always represented with an number composed of minimum 4 digits and maximum 5 digits, as shown in the screen shot below:

 

Although the observed session tokens were never generated sequentially, the lack of a cryptographically strong PRNG for the session identifier, allows a malicious user to trivially guess the token. This attack can be easily automated.

For example, in Burp proxy, the cool feature of Intruder combined with a "number" payload and even a single thread would suffice to guess a valid session token in a reasonable time.

By targeting a "protected" page of SMEX administrative interface as a baseline request for Intruder and by examining the HTTP response, it is possible to infer whether the session token is valid or not.

Once a valid token is obtained, a malicious user can impersonate another user's session on the system and gain unauthorised access to the SMEX administrative interface.

References:

Trend Micro Reference: http://esupport.trendmicro.com/solution/en-US/1109669.aspx
CVE reference: http://www.cvedetails.com/cve/CVE-2015-3326/
Session Prediction: https://www.owasp.org/index.php/Session_Prediction



Comments

Post a Comment

Popular posts from this blog

Pwning a thin client in less than two minutes

Have you ever encountered a zero client or a thin client? It looks something like this...

If yes, keep reading below, if not, then if you encounter one, you know what you can do if you read below...

The model above is a T520, produced by HP - this model and other similar models are typically employed to support a medium/large VDI (Virtual Desktop Infrastructure) enterprise.

These clients run a Linux-based HP ThinPro OS by default and I had a chance to play with image version T6X44017 in particular, which is fun to play with it, since you can get a root shell in a very short time without knowing any password...

Normally, HP ThinPro OS interface is configured in a kiosk mode, as the concept of a thin/zero client is based on using a thick client to connect to another resource. For this purpose, a standard user does not need to authenticate to the thin client per se and would just need to perform a connection - e.g. VMware Horizon View. The user will eventually authenticate through the c…

UXSS in McAfee Endpoint Security, www.mcafee.com and some extra goodies...

During the HITB2017AMS talk given in Amsterdam with @Steventseeley, I promised that I would have disclosed vulnerabilities affecting a security vendor product other than Trend Micro.

For those who have come to my blog for the first time and are looking at "insecurities" of security vendors, you might be interested as well on how we found 200+ remote code execution vulnerabilities in Trend Micro software...

But this blog post is dedicated to two McAfee products instead: McAfee Endpoint Security and SiteAdvisor Enterprise (now part of McAfee Endpoint Security). For simplicity, I will just refer to McAfee Endpoint Security for the rest of this post.

First let's demonstrate a particular type of XSS, a UXSS, considering that fact that it only affects the McAfee Endpoint Security plugin and does not depend on a particular web site or web application.

There are two different injection points:

-UXSS when user visits a red labelled web site - the payload is rendered in the BlockP…

Alcatel Lucent Omnivista or: How I learned GIOP and gained Unauthenticated Remote Code Execution (CVE-2016-9796)

It is time for another advisory or better a blog post about Alcatel Lucent Omnivista and its vulnerabilities. Omnivista is a central management network tool and it is typically used in medium/large organisation with a complex VoIP/SIP infrastructure.



Interestingly enough, this software belongs to the niche of "undownloadable" software and it requires a license to work as well. My "luck" came during an engagement where it was already installed and this post documents one of the many 0days discovered during such audit.

The reasons why I wanted to dedicate a single blog post on this vulnerability are several.

First, remote code execution (RCE) is always a sweet bug to show. Second, I strongly believe that documenting vulnerabilities in applications using old protocols and standards, respectively GIOP and CORBA, can be beneficial for the infosec community, since no many examples of vulnerabilities in such applications are available or published on the Internet.

Actuall…