Threat Level: green Handler on Duty: Didier Stevens

SANS ISC: Special Microsoft Bulletin Patching Remote Code Execution Flaw in OpenType Font Drivers - SANS Internet Storm Center SANS ISC InfoSec Forums


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Special Microsoft Bulletin Patching Remote Code Execution Flaw in OpenType Font Drivers

Microsoft just released a special "out fo band" security bulletin with a patch for a remote code execution vulnerability in Windows' OpenType font drivers. The update replaces a patch released last week (MS15-077). Microsoft rates the vulnerability critical for all currently supported versions of Windows. Microsoft says in it's bulletin, that it had information that the vulnerability was public, but had no indication that it was actively exploited. MS15-077 had been exploited at the time the MS15-077 bulletin was released last week. As a workaround, users may remove the font driver, but this may cause applications that rely on it to not be able to display certain fonts.

# Affected Contra Indications - KB Known Exploits Microsoft rating(**) ISC rating(*)
clients servers
MS15-078 Remote Code Execution Vulnerability in Microsoft Font Driver (Replaces MS15-077 )
Adobe Type Manager Library atmfd.dll
CVE-2015-2426
KB 3079904 Exploits Detected against related vulnerability CVE-2015-2387 (see MS015-077). Vulnerability may have been public. Severity:Critcal
Exploitability: 0
Critical
or
PATCH NOW
Important
We will update issues on this page for about a week or so as they evolve.
We appreciate updates
US based customers can call Microsoft for free patch related support on 1-866-PCSAFETY
(*): ISC rating
  • We use 4 levels:
    • PATCH NOW: Typically used where we see immediate danger of exploitation. Typical environments will want to deploy these patches ASAP. Workarounds are typically not accepted by users or are not possible. This rating is often used when typical deployments make it vulnerable and exploits are being used or easy to obtain or make.
    • Critical: Anything that needs little to become "interesting" for the dark side. Best approach is to test and deploy ASAP. Workarounds can give more time to test.
    • Important: Things where more testing and other measures can help.
    • Less Important patches for servers that do not use outlook, MSIE, word etc. to do traditional office or leisure work.
    • The rating is not a risk analysis as such. It is a rating of importance of the vulnerability and the perceived or even predicted threats.

       

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Johannes B. Ullrich, Ph.D.
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I will be teaching next: Defending Web Applications Security Essentials - SANS Security West 2019

Johannes

3481 Posts
ISC Handler
Does this only impact console display, or could things like document imaging and print servers also be affected?
Rich

2 Posts
I assume this also affects Windows Server 2003, but no patch is being released, is that correct?
Rich
5 Posts
From the sounds of things, yes, this also affects 2003.
Sounds as if this is different iteration of a issue patched with MS15-077 which was applicable to Server 2003 just a few days ago prior to the EoL support. Also, all other versions of Windows are impacted, so again, highly likely.
Anonymous
Customers with extended support contracts will get a patch for Windows 2003 server, per our TAM.
Paul

44 Posts
Some say that this vulnerability is related to Hacking Team's exploit for Adobe's open type font manager. Even NIST says so https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-2426.

However a reddit user says that it's a pool overflow bug, judging by bindiff results https://www.reddit.com/r/netsec/comments/3dyuwv/ms15078_remote_code_execution_in_all_versions_of/cta3lsx

Does anyone know what is really going on?
MD

11 Posts
Any news on Windows XP being vulnerable? Obviously everyone should have migrated away but it's always nice to know...
MD
2 Posts
Consensus seems to be this was a Hacking Team exploit. Unless something more substantial comes out I'll have to side with NIST, FireEye's and TrendMicros's word.

FireEye Reference = http://www.csoonline.com/article/2950239/vulnerabilities/microsoft-releases-out-of-band-patch-for-all-versions-of-windows.html
TrendMicro Reference = http://blog.trendmicro.com/trendlabs-security-intelligence/hacking-team-leak-uncovers-another-windows-zero-day-ms-releases-patch/

In the end, I don't think it really matters where it came from. It's a vulnerability that needs to be patched. I have a feeling us in the InfoSec community are going to be dealing with an influx of these vulnerabilities in the coming weeks due to the Hacking Team breach and new information coming to light. Suppose it's better than letting the vulnerabilities continue to run in the wild though.
Anonymous
makes you wonder just how many 0-days are lurking out there, though. Ugh.
John

88 Posts
Nobody needs use to check whether XP is affected.
Everybody can query the Microsoft Update Catalog:
https://catalog.update.microsoft.com/v7/site/ScopedViewInline.aspx?updateid=ce9ea6ce-981c-4812-8895-baae01efb307
Anonymous
Users of Windows Server 2003 should remove the registry entry which lets CSRSS.EXE load this font driver:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Font Drivers]
"Adobe Type Manager"=-
Anonymous
Hey all,
I am a bit dumbfounded that with regard to this critical vulnerability.
There's a lot of talking on how to patch, what to patch, when to patch, why to patch.
What I can't find anywhere (at least in the top let's say 20 sites dedicated to CVE-2015-2426) is a how to on... how to assess a potentially malicious file in order to determine whether an attempt to compromise is taking place.
I mean, something along the lines of: you have a user reporting a docx file, what to look for, where to look within the file in order to be able to draw a conclusion.
I would really appreciate a bit of direction in this.
Regards,
Anonymous

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