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An infection from Rig exploit kit, (Mon, Jun 17th)

Introduction

Rig exploit kit (EK) is one of a handful of EKs still active as reported in May 2019 by Malwarebytes.  Even though EKs are far less active than in previous years, EK traffic is still sometimes noted in the wild.  Twitter accounts like @nao_sec, @david_jursa, @jeromesegura, and @tkanalyst occasionally tweet about EK activity.  Today’s diary reviews a recent example of infection traffic caused by Rig EK.

Recent developments

For the past year, Rig EK has been using Flash exploits based on CVE-2018-8174 as noted in this May 2018 blog post from @kafeine.  Since then, other sources have reported Rig EK delivering a variety of malware like the Grobios Trojan or malware based on a Monero cryptocurrency miner.  Like other EKs, Rig EK is most often used in malvertising distribution campaigns.  In today’s infection, Rig EK delivered AZORult, and the infection followed-up with other malware I was unable to identify.

Infection traffic

I used a gate from malvertising traffic in a recent tweet from @nao_sec.  See images below for details.


Shown above:  Traffic from the infection filtered in Wireshark.


Shown above:  A closer look at the Rig EK traffic.


Shown above:  Rig EK landing page.


Shown above:  Rig EK sends a Flash exploit.


Shown above:  Rig EK sending its malware payload (encrypted over the network, but decoded on the infected host).


Shown above:  An example of AZORult post-infection traffic.


Shown above:  Follow-up malware EXE retrieved by my infected Windows host.

Indicators of Compromise (IOCs)

Redirect domain that led to Rig EK:

  • 194.113.104[.]153 port 80 – makemoneyeasy[.]live – GET /

Rig EK:

  • 5.23.55[.]246 port 80 – 5.23.55[.]246 – various URLs

AZORult post-infection traffic:

  • 104.28.8[.]132 port 80 – mixworld1[.]tk – POST /mix1/index.php

Infected Windows host retrieved follow-up malware:

  • 209.217.225[.]74 port 80 – hotelesmeflo[.]com – GET /chachapoyas/wp-content/themes/sketch/msr.exe

SHA256 hash: a666f74574207444739d9c896bc010b3fb59437099a825441e6c745d65807dfc

  • File size: 9,261 bytes
  • File description: Flash exploit used by Rig EK on 2019-06-17

SHA256 hash: 2de435b78240c20dca9ae4c278417f2364849a5d134f5bb1ed1fd5791e3e36c5

  • File size: 354,304 bytes
  • File description: Payload sent by Rig EK on 2019-06-17 (AZORult)

SHA256 hash: a4f9ba5fce183d2dfc4dba4c40155c1a3a1b9427d7e4718ac56e76b278eb10d8

  • File size: 2,952,704 bytes
  • File description: Follow-up malware hosted on URL at hotelesmeflo[.]com on 2019-06-17

Final words

My infected Windows host retrieved follow-up malware after the initial AZORult infection.  However, I was using a virtual environment, and I didn’t see any further post-infection traffic, so I could not identify the follow-up malware.

A pcap of the infection traffic along with the associated malware and artifacts can be found here.


Brad Duncan
brad [at] malware-traffic-analysis.net

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Sysmon Version 10: DNS Logging, (Sun, Jun 16th)

Sysmon Version 10.0 brings DNS query logging.

By default, DNS query logging is not enabled. You need to provide a configuration file, like this simple config.xml:

 
   
   
 

This config file will log all DNS queries: using onmatch=”exclude” without any filters excludes no events at all.

Remark also that the event is DnsQuery (and not DNSQuery as listed on Sysinternals page for Sysmon).

Here is a simple “ping google.com” command, resulting in event 22 being logged in the Sysmon Windows event log:

Remark that event 22 does not only log the DNS query, but also the replies and the program that issued the query.

If you enable DNS logging like I did (not exclusions) ina production environment, you will have too many events. SwiftOnSecurity’s Sysmon config can help you exclude many queries that are not important for IR.

Sysmon DNS logging did not work on my Windows 7 VM, but I just noticed that Sysmon version 10.1 was released, I will test this again.

 

Didier Stevens
Senior handler
Microsoft MVP
blog.DidierStevens.com DidierStevensLabs.com

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A few Ghidra tips for IDA users, part 4 – function call graphs, (Fri, Jun 14th)

One of the features of IDA that we use in FOR610 that can be helpful for detecting malicious patterns of API calls is the feature for creating a graph of all function calls called from the current function and any functions that it calls. The graph itself isn’t all that pretty to look at, but it allows us to see if all the APIs in a particular pattern (code injection, for example) are made in the proper order. We do this by choosing View > Graphs > ‘Xrefs from’ in the menus. In IDA, it looks like the following.

When I first went looking for an equivalent in Ghidra, I had a hard time finding it. I eventually found it in the Window menu.

But, when I first ran it, I only saw the functions that call this one (which is nice, you need to do Xrefs to in IDA to see these) and the ones that this function called, so only 1 level deep in each direction. That wasn’t going to cut it because sometimes the API calls that we’re interested in are buried several levels of calls deep.

However, after looking at it for a while, I discovered that if you righ-click on any node in the bottom row, you get a menu that allows you to extend it another level deeper, by selecting ‘Show Outgoing Level Edges’. Okay, this is promising.

After selecting that, I got the following

Those lines are still somewhat confusing, but you can move the individual nodes in the graph around to make the relationships clearer. Also, have I mentioned how nice a big monitor is when you are reversing (in either IDA or Ghidra). And, since you have the control to expand one level at a time, I may even come to like this more than IDA’s graph. If the graphs are somewhat confusing to you, though, you can also use the Show Function Call Tree button to bring up a couple of pains that show the same info textually

On the left side are the incoming calls

And on the right, the outgoing calls.

And you can then expand any of the functions which may call other functions (those with the little box in front)

For me, personally, that may work even better, but you may prefer the graph.

I think I’ll wrap up this entry here. If you are at SANSFIRE next week, please come to the SANS ISC annual State of the Internet panel on Monday evening in Salon 1. You can also stop by and say ‘Hi!’ I’ll be TA-ing for Lenny Zeltser in FOR610. As with all the other entries in the series if you have other thoughts or tips, feel free to comment here, send me an e-mail, or drop into our slack channel. Until next time, …

—————
Jim Clausing, GIAC GSE #26
jclausing –at– isc [dot] sans (dot) edu

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What is "THAT" Address Doing on my Network, (Thu, Jun 13th)

Disclosure: ISC does not endorse any one particular vendor. That said, you may recognize what type of firewall I use 🙂

So this all started with a strange log entry with SYN packet going to a RFC1918 [1] Address. Now, that address is not in regular use on my network, all the more puzzling.

Below is the log entry in question, which indicates it is from my main gaming rig (i7-9700K, 128GB DDR4, (2) GTX1080 SLI, M.2 1TB). This desktop is only really used for gaming, not much browsing and very little else (Discord, etc). So lower risk (at least I thought).

First step I took, was to take a look at a PCAP from the Firewall’s view, so I setup my filter on the IP in question as a destination.

Started the capture.

As expected, not much there, just a SYN packet. 

What to do now? To the TCPView [2] BatMAN!!! It took a few moments for the “offending” process to pop up, so this capture was in real-time (or in other words, I clicked the “Capture” button when I saw it).

And yes, my gaming rig is FRANK, and the beauty of letting you see part of my domain name? Is there is an english joke in there somewhere :). So Found the Tobii service as the ‘offender.’ Tobii Gaming [3] makes eye tracking hardware (fantastic aiming assistant and helps me keep up with those that use mouse/keyboard). This hardware I happen to use when playing some games *cough* Division 2 *cough* so that got less interesting. We need a few more things, but we are starting to draw a conclusion. 

 

Now to break out Process Hacker [4] and dump it out of memory.

Once dumped, we went straight to our reliable ‘super expensive’  tools grep and strings (that’s sarcasm, they are open source :)…

Running a dump using a couple of switches with grep after sending the dmp through strings, we can see on either side of the IP.

cat | strings | grep -B 10 -A 10  

It did produce an interesting artifact, a public key, but cemented the conclusion that this was likely developer code left over in the compile. Let me know what you think? Now that we’ve taken a look, I plan to update the Tobii engine and suspect that this problem will go away. If there is anyone from Tobii that is reading, thanks for the support!

 

Summary

Not ‘every’ indicator has to nessessarily be evil and with some basic tools, you can start to put a story together on things. In this case, just the PCAP engine on my firewall, Process Hacker and TCPView, then on my *nix platform, cat, strings and grep. Remember, humans (for now) write most code and we all write perfect code right?

 

[1] https://tools.ietf.org/html/rfc1918

[2] https://docs.microsoft.com/en-us/sysinternals/downloads/tcpview

[3] https://gaming.tobii.com/

[4] https://processhacker.sourceforge.io/

 

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.

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