[Snort-sigs] Malicious Chrome Extensions

Stanwyck, Carraig - ASOC, Kansas City, MO Carraig.Stanwyck at ...4154...
Wed Nov 9 01:06:22 EST 2016

Good Evening,

Another quick update.  We identified more traffic with this rule from yet another domain on the list of Viacheslav Zinkevich registered sites (whywhat.top).  For anybody not tracking, I've attached the list of domains again.  This is now the 5th domain registered by this guy that's associated with malicious chrome extensions.

Carraig Stanwyck

From: Stanwyck, Carraig - ASOC - Kansas City, MO
Sent: Thursday, August 25, 2016 1:26 AM
To: emerging-sigs at ...3694...; snort-sigs at lists.sourceforge.net
Subject: RE: Malicious Chrome Extensions

I just wanted to follow up...

The published rule has already caught another malicious extension from a different domain that I included in the original text file of suspected domains, so it appears my suspicious were correct.  That said, I still have little information.  We have identified 3 infected hosts, but were only able to retrieve the extensions list on one of the machines.  Once the extensions were cleared, the traffic stopped.  That said, I haven't identified the malicious extension.

Installed Extensions on Infected Host:

-          Amazon Assistant for Chrome

-          Ambient Aura

-          Chromarks - Chrome Bookmarks Menu

-          Extensions Manager (aka Switcher)

-          Fair AdBlock (by STANDS)

-          Fair Adblock App (by STANDS)

-          Fair Ads (by STANDS)

-          Google Cast

-          Google Chrome to Phone Extension [DEPRECATED]

-          Google Contacts Launcher

-          Google Docs Offline

I haven't found anything malicious on these when researching them, but your move may vary.  Deleting them all stopped the malicious traffic.

Carraig Stanwyck

From: Stanwyck, Carraig - ASOC - Kansas City, MO [mailto:Carraig.Stanwyck at ...180.....4154...]
Sent: Friday, August 05, 2016 7:32 AM
To: emerging-sigs at ...3694...<mailto:emerging-sigs at ...3694...>; snort-sigs at ...184...ists.sourceforge.net<mailto:snort-sigs at lists.sourceforge.net>
Subject: [Snort-sigs] Malicious Chrome Extensions

Good Morning,

I have identified what I am almost certain is traffic from malicious chrome extension infections on our network.  The IOC in my case is hxxp://brainlog.top, which has the same registrar (VIACHESLAV ZINKEVICH) as 100+ other suspicious domains (attached), including 4chan-plus.com, which has a reddit PSA (https://www.reddit.com/r/chrome/comments/4caqdv/psa_remove_4chan_plus_its_inserting_malware_into/) for the same activity we're seeing here.

Proposed rule:
alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"ET MALWARE Malicious Chrome Extension"; flow:established,to_server; content:"page?url="; http_uri; fast_pattern; content:"user"; http_uri; content:"iframe="; http_uri; content:!"Referer|3a|"; http_header; classtype:trojan-activity; sid:123456; rev:1; )

It'd be pretty easy to add some pcre into it if necessary, the patterns are consistent.

Example URIs (2 separate infections, delineated by the string following "user"):

Carraig Stanwyck

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