Monday, 21 May 2018

Weekly TrickBot Analysis - End of w/c 14-May-2018 to A-1000195, B-1000068, and C-1000185

Here are the results of my analysis of TrickBot Banking Trojan mcconfs shared up to the end of the week commencing 14th May 2018. This analysis covers 2,288 unique C2 IP addresses used in 430 mcconfs across 247 versions, with highest versions of A-1000195, B-1000068, and C-1000185.

Since its first use in approximately October 2016, TrickBot has frequently issued new versions of its XML configuration file, mcconf. Originally there was a single chain of config versions which started at 1000002. (There may have been a 1000001 but it is not been shared publicly.) I refer to this original sequence as iteration A. In November 2017 TrickBot mcconfs were issued for older version numbers than the current iteration A configs, but with different command and control (C2) servers to those in that version's iteration A config. This indicated the start of iteration B, a new sequence of configs believed to be for a second botnet. While there is some overlap of the C2 servers between iteration A and iteration B, the majority of C2 servers are specific to an iteration (hence botnet). As of late March 2018 another iteration, iteration C, was started, once again repeating previously used version numbers but with different C2 server lists.

The following graph shows the rate of discovery of TrickBot versions in the wild, based on shared mcconfs. The flatter the line, the more frequently versions are discovered. Ignore the long almost vertical lines which coincide with the switch from one iteration to the next. These vertical lines are purely an artefact of graphing the data in a single series. (Note: Full size versions of all the graphs and tables are available via the link at the end of this post.)

There were three new config versions discovered in the week commencing 14th May 2018 (A-1000193, A-1000194, and A-1000195), three the week before, and six the week before that. All of the three new config versions extend the iteration A botnet, taking this to 1000195. The secondary, iteration B, botnet was not extended in the discovered versions and remains unchanged since 1000068 of 28th February 2018. The tertiary, iteration C, botnet was also not extended in the discovered versions and remains unchanged since the 1st May 2018 at 1000185.

TrickBot Version Discovery Dates

The following graph shows the number of server entries using ports:
  • 443 (HTTPS);
  • 444 (Simple Network Paging Protocol) -- INACTIVE;
  • 445 (IBM AS Server Mapper) -- INACTIVE;
  • 449 (Cray Network Semaphore Server); and 
  • 451 (SMB) -- INACTIVE.
In the last month the length of the C2 server lists has stabilised. In the case of iteration A, its C2 server lists have contained approximately 30 server entries.

TrickBot SRV Port Usage

The following table shows the top 25 servers (of  2,288 unique) used within the 247 versions. This week the top four and bottom 16 of the table remained static, while there was some minor reordering between position 5 and 9.

TrickBot Top 25 SRV

The following table shows the breakdown of detected TrickBot campaign 'gtag' (group tags) values used in the 430 mcconfs analysed. (Yes, I know it's unreadable - it's just here as a guide to show what's in the downloadable zip file at the bottom of the post.)

TrickBot gtag Breakdown

58 C2 servers were used in the mcconfs from this week, of which 34 (59%) were new. The following graph shows the proportional server count of mcconfs shared each week (when compared to the greatest count in a week), along with the percentage churn of the servers.

TrickBot SRV Count and Churn

The BGP prefix registrations for the C2 server IP addresses continue to be heavily biased to ASN routed through RU (and so the graph below's Y-axis is cut short to allow clearer viewing of other country counts). The new servers' IP addresses are associated with ASN routed to: 16xRU, 4xUA, 2xAU, 2xCA, 2xIN, 2xLU, 1xBR, 1xCZ, 1xES, 1xPL, 1xTJ, and 1xUS.

TrickBot SRV IP Address BGP Prefix Country Codes

The following map shows the geographical location of 53 (those with location data) of 53 (scanned by Shodan) of the 58 C2 server IP addresses used in the analysed configs.

According to Shodan's most recent data:
  • 19 are Ubiquiti devices.
  • 24 are running Dropbear SSH, 20 are running OpenSSH, 14 are running nginx, 11 are running Apache, 7 are running Exim, two are running MySQL, one is running Postfix, and one is running ProFTP.
TrickBot C2 Server IP Locations For New Configs

The following table shows the BGP allocations of C2 servers' IP addresses to country by TrickBot version. (Once again, I know it's unreadable - it's just here as a guide to show what's in the downloadable zip file at the bottom of the post.)

TrickBot SRV IP Address BGP Prefix Country Codes By Version

Finally, the following table shows the top 25 BGP prefixes used by TrickBot for C2 servers.

TrickBot Top 25 BGP Prefixes

Full size versions of the images included in this post are available here. I've also created a page documenting the various discrepancies identified in TrickBot's mcconf files.

Thanks to hasherezade, mpvillafranca94, JR0driguezB, 0bscureC0de, VK_Intel, K_N1kolenko, botNET___, ArnaudDlms, StackGazer, voidm4p, James_inthe_box, MakFLwana, _ddoxer, spalomaresg, virsoz, moutonplacide, JasonMilletary, Ring0x0, precisionsec, Techhelplistcom, pollo290987, MalHunters, coldshell, 0x7fff9, kobebryamV2, dvk01uk, benkow_, and MalwareSecrets.