Thursday, 26 April 2018

Weekly TrickBot Analysis - End of w/c 16-Apr-2018 to A-1000182, B-1000068, and C-1000173

Here are the results of my analysis of TrickBot Banking Trojan mcconfs shared up to the end of the week commencing 16th April 2018. This analysis covers 2,115 unique C2 IP addresses used in 397 mcconfs across 224 versions, with highest versions of A-1000182, B-1000068, and C-1000173.

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 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.

Iteration A only = 1,727 C2 servers
Iteration B only = 329 C2 servers
Iteration C only = 58 C2 servers
Iteration A & B = 13 C2 servers
Iteration A & C = 2 C2 server
Iteration B & C = 0 C2 servers
Iteration A, B & C = 0 C2 servers

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 11 new config versions discovered in the week commencing 16th April 2018 (A-1000176, A-1000177, A-1000178, A-1000179, A-1000180, A-1000181, A-1000182, C-1000169, C-1000171, C-1000172, and C-1000173), six the week before, and seven the week before that. Of the 11 new config versions, seven extend the iteration A botnet, taking this to 1000182. The secondary, iteration B, botnet was not extended in the discovered versions and remains unchanged since 1000068 of 28th February 2018. Four of the new config versions started off a new tertiary, iteration C, botnet, starting at C-1000169.

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).
As with last week, the iteration A configs have pushed toward (and temporarily just over) 30 C2 servers. A single :451 (SMB) server remained during the week also. The new iteration C configs have been a similar length to the iteration B ones from earlier in the year. So far, with a cap of 20 C2 servers in their lists.

TrickBot SRV Port Usage

The following table shows the top 25 servers (of  2,115 unique) used within the 212 versions. While server 82[.]214[.]141[.]134:449 extended its lead at the top, additionally 185[.]159[.]128[.]158:443 jumped from a new entry last week up to the middle of the table. Lastly, 176[.]121[.]215[.]149:449 entered at the bottom of the table.

TrickBot Top 25 SRV

The following table shows the breakdown of detected TrickBot campaign 'gtag' (group tags) values used in the 397 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

106 C2 servers were used in the mcconfs from this week, of which 81 (76%) were new. 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: 39xRU, 21xUA, 7xFR, 3xNL, 3xUS, 2xLT, 1xCA, 1xGB, 1xHU, 1xLU, 1xRS, and 1xTJ.

TrickBot SRV IP Address BGP Prefix Country Codes

The following map shows the geographical location of 91 (those with location data) of 92 (scanned by Shodan) of the 106 C2 server IP addresses used in the analysed configs.

According to Shodan's most recent data:
  • 13 are Ubiquiti devices and two are MikroTik devices.
  • 61 are running OpenSSH, 27 are running nginx, 13 are running Dropbear SSH, nine are running Apache, nine are running Exim, six are running Postfix, three are running MySQL, two are running IIS, and one is running Pro FTP.
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.

Thanks to @hasherezade, @mpvillafranca94, @JR0driguezB, @0bscureC0de, @virsoz, @spalomaresg, @VK_Intel, @K_N1kolenko, @botNET___, @ArnaudDlms, @StackGazer,@voidm4p, @James_inthe_box, @MakFLwana, @_ddoxer, @moutonplacide, @JasonMilletary,@Ring0x0, @precisionsec, @Techhelplistcom, @pollo290987, @MalHunters, @coldshell, @0x7fff9 and @MalwareSecrets for sharing the mcconfs.