Blog

Kitten.gif: Meet the Sabbath Ransomware Affiliate Program, Again

Tyler McLellan, Brandan Schondorfer
Nov 29, 2021
10 mins read
Ransomware
Threat Research
Uncategorized Groups (UNC Groups)

In September 2021, Mandiant discovered a post on exploit.in seeking partners for a new ransomware affiliate program. By October 21, 2021, the 54BB47h (Sabbath) ransomware shaming site and blog were created and quickly became the talk of security researchers. In contrast with most other affiliate programs, Mandiant observed two occasions where the ransomware operator provided its affiliates with pre-configured Cobalt Strike BEACON backdoor payloads. While the use of BEACON is common practice in ransomware intrusions, the use of a ransom affiliate program operator provided BEACON is unusual and offers both a challenge for attribution efforts while also offering additional avenues for detection.

Mandiant Advanced Practices began proactively identifying similar BEACON infrastructure across past Mandiant Consulting engagements, Advanced Practices external adversary discovery program, and commercially available malware repositories. Through this analysis, Advanced Practices linked the new Sabbath group to ransom activity under previously used names including Arcane and Eruption.

UNC2190, operating as Arcane and Sabbath, has targeted critical infrastructure including education, health, and natural resources in the United States and Canada since June 2021. The targeting of critical infrastructure by ransomware groups has become increasingly concerning as evidenced by governments moving to target ransomware actors as national security level threats with particular attention to groups that target and disrupt critical infrastructure.

Stealthy Ransomware

In July 2020, UNC2190 deployed ROLLCOAST ransomware while branded as Eruption. Mandiant has not observed samples of UNC2190-deployed ransomware in 2021 and no samples of ROLLCOAST have ever been submitted to VirusTotal. In the following sections, some of the technical reasons why UNC2190’s ransomware has evaded capture and discovery will be discussed.

Next Level Extortion and ‘Backup Killers’

Sabbath first came to light in October 2021 when the group publicly shamed and extorted a US school district on Reddit and from a now suspended Twitter account, @54BB47h. During this recent extortion, the threat actor demanded a multi-million-dollar payment after deploying ransomware. Media reporting indicated that the group took the unusually aggressive step of emailing staff, parents and even students directly to further apply public pressure on the school district.

@54BB47h on Twitter
@54BB47h on Twitter

UNC2190 uses a multifaceted extortion model where ransomware deployment may be quite limited in scope, bulk data is stolen as leverage, and the threat actor actively attempts to destroy backups.

Ransom note example
Ransom note example

The threat actor has utilized public data leaks to extort the victims to pay ransom demands. While Sabbath operates a public shaming blog, Mandiant only observed victims being publicly extorted beginning in mid-November 2021, where 6 victims were added over the span of two days. Previously under the Arcane brand, Mandiant observed three victims publicly extorted in June 2021.

Source: Reddit SecOpsDaily
Source: Reddit SecOpsDaily

Arcane Rebranded

Mandiant discovered that the new Sabbath public shaming web portal and blog first published in October 2021 is nearly identical to that of Arcane from June 2021. This included the same text content, and minor changes to the name, color scheme, and logo. The threat actor kept consistent grammatical errors in their updated web forums.

Sabbath 54bb47h5qu4k7l4d7v5ix3i6ak6elysn3net4by4ihmvrhu7cvbskoqd.onion Website October 2021
Sabbath 54bb47h5qu4k7l4d7v5ix3i6ak6elysn3net4by4ihmvrhu7cvbskoqd.onion Website October 2021
thearcane.top website June 2021
thearcane.top website June 2021

Behind the scenes, few technical changes were made to the affiliate model used to carry out the attacks between the rebranding from Arcane to Sabbath. BEACON samples and infrastructure from both ransomware affiliate services remained unchanged. The malware sample PE compile times were identical on Themida-packed BEACON droppers used by the threat actor (such as md5 6bd1a3849bb9d5f9ac5b4f4049081334 and 38667bc3ad2dcef35a5f343a5073e3f2).

Hunting for UNC2190 BEACON Samples

Since July 2020, UNC2190 has utilized BEACON with unique Malleable profile elements, including:

  • GET requests ending with kitten.gif, such as:
    • hxxps://markettc.biz/gifs/ZsoCzxU-X-5D3ZhV2zzKgc8SHhygCYmWpBRCS_mRV_SZxyWaaSPw7FFtcZ66twQ_uTDp5Edls
      mRa6K8GPtMVBnKOHhM6EgcnE4znZPiyXskZJXmHLSYAnkpLwhOrxyCoRkFthelDg
      VnuW7k3UVzDjEz3W4xuxSKBq2DuseaG-F0dob1M/kitten.gif
  • POST variable “image_url”, points to a specific image hosted on popular Russian social media site VK: hxxps://sun9-23.userapi.com/G4JvdZDEfLdIPlNN1-JkMGQ2unf2KEIV54Om5g/abJ70jGHfVk.jpg
  • User agent, such as: "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.163 Safari/537.36"

Mandiant discovered additional infrastructure similarities utilized by UNC2190 including:

  • Actual IPs masked using a cloud service.
  • Self-signed TLS certificate common name “Microsoft IT TLS CA 5

Evolving to Evade Antivirus Detection

In March 2021, Mandiant Consulting observed an intrusion for another tracked UNC group where antivirus had detected and blocked two attempts to load a BEACON payload which Mandiant attributes to UNC2190. Subsequently, a different tracked threat actor deployed  different ransomware at this victim with more success. Starting July 6, 2021, Mandiant detected the use of Themida to pack UNC2190 BEACON malware and protect it from detection.

ROLLCOAST Ransomware Deep Dive

In July 2020, Mandiant first detected ROLLCOAST ransomware usage by UNC2190. ROLLCOAST

is a ransomware program that encrypts files on logical drives attached to a system. ROLLCOAST is a Dynamic Linked Library (DLL) with no named exports. When observed by Mandiant it uniquely had only one ordinal export 0x01. This suggested the sample was designed to avoid detection and be invoked within memory, possibly through BEACON provided to affiliates. Incident responders working on similar intrusions should capture memory for analysis. ROLLCOAST was not written to disk during this intrusion and was only detected in memory by Mandiant.

The malware begins by checking the system language and exits if it detects a non-supported language code from the table below. Many other ransomware families have similar checks to avoid encrypting systems in Russia and other Commonwealth of Independent States member countries presumably to avoid attracting the attention of law enforcement in countries where the ransomware operator and affiliates are more likely to reside.

Language Exclusions

ROLLCOAST will exit if the system language matches one of the following:

Language ID

Description

0x419

Russian (Russia)

0x41A

Croatian (Croatia)

0x41B

Slovak (Slovakia)

0x41C

Albanian (Albania)

0x41D

Swedish (Sweden)

0x41E

Thai (Thailand)

0x41F

Turkish (Turkey)

0x420

Urdu (Islamic Republic of Pakistan)

0x421

Indonesian (Indonesia)

0x422

Ukrainian (Ukraine)

0x423

Belarusian (Belarus)

0x424

Slovenian (Slovenia)

0x425

Estonian (Estonia)

0x426

Latvian (Latvia)

0x427

Lithuanian (Lithuania)

0x428

Tajik (Cyrillic, Tajikistan)

0x429

Persian (Iran)

0x42A

Vietnamese (Vietnam)

0x42B

Armenian (Armenia)

0x42C

Azerbaijani (Latin, Azerbaijan)

0x42D

Basque (Basque)

0x42E

Upper Sorbian (Germany)

0x42F

Macedonian (Former Yugoslav Republic of Macedonia)

0x430

Southern Sotho (South Africa)

0x431

Tsonga (South Africa)

0x432

Setswana (South Africa)

0x433

Venda (South Africa)

0x434

isiXhosa (South Africa)

0x435

isiZulu (South Africa)

0x436

Afrikaans (South Africa)

0x437

Georgian (Georgia)

0x438

Faroese (Faroe Islands)

0x439

Hindi (India)

0x43A

Maltese (Malta)

0x43B

Sami, Northern (Norway)

0x43D

Yiddish (World)

0x43E

Malay (Malaysia)

0x43F

Kazakh (Kazakhstan)

0x440

Kyrgyz (Kyrgyzstan)

0x441

Kiswahili (Kenya)

0x442

Turkmen (Turkmenistan)

0x443

Uzbek (Latin, Uzbekistan)

0x444

Tatar (Russia)

Similarities to Tycoon

Mandiant compared elements of ROLLCOAST to elements of Tycoon ransomware and found some similarities:

  • Both ransomware families encrypt files using AES in GCM mode
  • Overlap between the ignored directories, files, and extensions including the ignored extension “.lolz”.

This suggests the developers modelled ROLLCOAST on, or copied elements from, Tycoon ransomware. ROLLCOAST and TYCOON differ in their overall implementations: TYCOON is a Java based ransomware whereas ROLLCOAST is not. In addition, there is functionality in the publicly reported TYCOON that ROLLCOAST does not appear to have (shell commands, backup tampering, firewall tampering, wmic).

ROLLCOAST Strings

FOUND DEVICE:

Start encryption of %s

[-] Failed to init dir traverse for: %s

Finished encryption of %s

Work out other countries. Don't be fool!

Hello from test.dll. Parameter is '%s'

Hello from test.dll. There is no parameter

Microsoft Primitive Provider

[-] AES FAILED 1: STATUS_NOT_FOUND

[-] AES FAILED 1: STATUS_INVALID_PARAMETER

[-] AES FAILED 1: STATUS_NO_MEMORY

[-] AES FAILED 1: UNDEFINED

ChainingModeGCM

ROLLCOAST Encrypted File Naming Convention

Files are encrypted and renamed to this format: <original_filename_and_extension>.[<upper_hex_string>].<ransom name>

Example encrypted file recovered from VirusTotal:

covid results from <redacted>.pdf.[6EEC0F355072<redacted four digits>].54bb47h

Conclusion

Although UNC2190 is a lesser known and potentially a smaller ransomware affiliate group, it’s smaller size and repeated rebranding has allowed it to avoid much public scrutiny. In Mandiant’s 2021 Trends and 2022 Predictions report, ransomware data theft operations affecting healthcare are noted as having increased from January 2020 to June 2021, despite some groups claiming they would avoid targeting hospitals. UNC2190 has continued to operate over the past year while making only minor changes to their strategies and tooling, including the introduction of a commercial packer and the rebranding of their service offering. This highlights how well-known tools, such as BEACON, can lead to impactful and lucrative incidents even when leveraged by lesser-known groups.

Acknowledgements

With thanks Joshua Shilko for analytical contributions, Barry Vengerik, Tufail Ahmed, Isif Ibrahima, Andrew Thompson, Jake Nicastro, Nick Richard, and Moritz Raabe for technical review, and all the Mandiant Researchers, Consultants, Advanced Practices External Collectors, and FLARE REs for support, research, and assistance to create the content of this post.

MITRE ATT&CK

Mandiant has observed UNC2190 use the following techniques:

ATT&CK Tactic Category

Techniques

Discovery

   T1016:        System Network Configuration Discovery

   T1057:        Process Discovery

   T1083:        File and Directory Discovery

   T1518:        Software Discovery

Impact

   T1486:        Data Encrypted for Impact

Discovery

   T1016:        System Network Configuration Discovery

   T1057:        Process Discovery

   T1083:        File and Directory Discovery

   T1518:        Software Discovery

Defense Evasion

   T1027:        Obfuscated Files or Information

   T1027.002:    Software Packing

   T1055:        Process Injection

   T1497:        Virtualization/Sandbox Evasion

   T1497.001:    System Checks

   T1564.003:    Hidden Window

Persistence

   T1136:        Create Account

Command and Control

   T1071.001:    Web Protocols

   T1573.002:    Asymmetric Cryptography

Resource Development

   T1587.003:    Digital Certificates

   T1608.003:    Install Digital Certificate

Execution

   T1059.001:    PowerShell

Yara Signatures

Note: FE_Hunting rules are designed to broadly capture suspicious files and are not designed to detect a particular malware or threat.

rule FE_Hunting_THEMIDA_strings_FEBeta

{

    meta:

        author = "Mandiant"

        date_created = "2021-10-26"

        date_modified = "2021-10-26"

        md5 = "7669f00b467e2990be182584b341c0e8"

        rev = 2

        sid = 415583

    strings:

        $themida = ".themida" nocase

    condition:

        uint16(0) == 0x5A4D and filesize < 20MB and (@themida[1] < 1024)

}

rule FE_Ransomware_Win64_ROLLCOAST_1

{

    meta:

        author = "Mandiant"

        date_created = "2020-07-15"

        date_modified = "2020-07-15"

        md5 = "45882426ecddb032981fd6c299b3cc47"

        rev = 2

    strings:

        $sb1 = { 48 8D [5] 48 8D ?? 24 ?? E8 [4-32] B? 30 00 00 00 [8-64] 25 FF F9 FF FF 0F BA E8 0B }

        $sb2 = { FF D? 85 C0 0F 84 [4] 48 8D [2-16] 83 E8 06 0F 84 [4] 83 E8 08 0F 84 [4] 83 E8 0F }

        $sb3 = { 41 B8 C5 02 00 00 0F 10 00 0F 10 48 10 0F 11 02 0F 10 40 20 0F 11 4A 10 0F 10 48 30 0F 11 42 20 0F 10 40 40 0F 11 4A 30 0F 11 42 40 89 4A 50 0F B6 48 54 88 4A 54 33 D2 49 8B C9 8B C2 48 8D 49 01 83 E0 0F FF C2 42 0F B6 84 08 [2] 00 00 30 41 FF 49 83 E8 01 75 E3 }

        $sb4 = { FF 15 [4] 05 E7 FB FF FF 83 F8 2B }

        $ss1 = "\x00Program Files\\" wide

        $ss2 = "\x00Program Files (x86)\\" wide

        $ss3 = "\x00.[\x00"

        $ss4 = "\x00].\x00"

    condition:

        (uint16(0) == 0x5A4D) and (uint32(uint32(0x3C)) == 0x00004550) and (uint16(uint32(0x3C)+0x18) == 0x020B) and all of them and (#ss1 > 5) and (#ss2 > 5)

}

rule FE_Ransomware_Win_ROLLCOAST_1

{

    meta:

        author = "Mandiant"

        date_created = "2020-07-15"

        date_modified = "2020-07-15"

        md5 = "45882426ecddb032981fd6c299b3cc47"

        rev = 2

    strings:

        $s2 = "\x00lolz\x00" wide

        $s3 = "\x00Start encryption of %s\x0a\x0a\x00" wide

        $s4 = "\x00Finished encryption of %s\x0a\x0a\x00" wide

        $s5 = "\x00FOUND DEVICE: \x0a\x00" wide

    condition:

        (uint16(0) == 0x5A4D and uint32(uint32(0x3C)) == 0x00004550) and all of them

}

Indicators

MALWARE FAMILY

Indicator

BEACON

aequuira1aedeezais5i.probes.space

BEACON

jeithe7eijeefohch3qu.probes.site

BEACON

datatransferdc.com

BEACON

farhadl.com

BEACON

markettc.biz

BEACON

probes.space

BEACON

tinysidney.com

BEACON

helpgoldr.com

BEACON

frankir.com

BEACON

greentuks.com

BEACON

45.79.55.129:443

BEACON

45.146.166.24:443

BEACON

45.147.230.221:2002

BEACON

aimee0febai5phoht2ti.probes.website

BEACON

cofeeloveers.com

BEACON

doratir.com

BEACON

gordonzon.com

BEACON

probes.site

BEACON

probes.website

BEACON

45.79.55.129:80

BEACON

45.141.84.182:443

BEACON

45.147.230.137:3001

BEACON

PE Compile time 1622138290 (2021/05/27 17:58:10)

MALWARE FAMILY

MD5

SHA1

SHA256

BEACON

ef3363dfe2515b826584ab53c4bb7812

3357fd8d5a253b7d84101e902480bf2dd2f7773c

da92878c314307a5e5c9df687ec19a402d93126b3818e5fb6b7241ab375d1e12

BEACON

f1b2f83aa08b8f6f01cac6bf686786d2

366390c3cd829d1172f02e564d35cfb2c667e9fc

0fb410b9a4d32a473b2ee28d4dc5e19a64524e107b980fc1ce8de2ad0dcc3302

BEACON

6bd1a3849bb9d5f9ac5b4f4049081334

a0928456f12e909ec03eadce449bc80f120bfbf8

298662f3fed24d757634a022c16f4124919b653f8bf7717e4f7a5b7d741729c0

BEACON

e94089ff2e0b93ce38076cca370cf8cc

dc3c26f305648a12484c17d6166397a002a93707

afd61168c1fae6841faa3860dca0e5839f1b7a3169184a1c04de5a9b88adfe5d

BEACON

ac76d6c5c223688edf2d53745036d594

5972b873977912adf06203b61685f32a6ccb9eee

a053408747e9b32721d25c00351c4ce9286208e8714780416f18cbe2536672a9

BEACON

64da229042dffddf5bb30a4a1d8b1f1e

3dc46fa5ebc87e8adcb6eaa0b407574506c957bb

b2ffd7d83e004308a97355a18529fe3528dcbbd7901fb28aaad9d46194469947

BEACON

1789f6177300d503289c482910f223d9

5c3f297bab8a5e93aac91a9df920c54bee2c836d

e302a958856208adeab4ab3cd6d2991e644798fabd57bb187a0aede314a4baa0

BEACON

dbfa3eb08d858d5bbb0cc72f497192b0

182e9d1026c63503aadb78bbc3788b7ba2cdb69a

8ddb23c90cb4133b4624127a1db75335a51e90d557c01e996ce33fe23f638e71

BEACON

79c6c4329a36df20a6abf67b01352b20

fc7b3d8beab604cf47203f4f9a2aa8594bd54fb7

1bbb11e526141af7bafb5d4db3671b1a01bb277fda047920995c1f2a4cb6654c

BEACON

6ae156c0a1900b6ff2c903a950d50dce

7b178842e1b53f163f869d9da3da32032fe29abb

1cd586852d2c06b0f7209c7a4da8f3d0de794f92e97b7c4405ad71c859dc2f50

BEACON

b0333d840e136326a2bd612fcf73fff0

8467b4f784156f2e508a3fed0ef0b6ddcf330c0d

79b47780382f54ca039ad248d8241e42a7ed6b1e4b75af836890e4e46c0f8737

BEACON

7669f00b467e2990be182584b341c0e8

2eaa91f38461d708ee6e94ec2f738f3cdfb229b7

f4ac75a045acee2cadbe9fa0e02bfd4ab4124018e00193930966b8141351115f

BEACON

60aec56cb2262ae46fc39c45fc814711

bb22515f2e8e4d5660dc8565869d966502a0123e

3edb237aeee6efad6f21f0f2c2037ec0f9f817197432de9759b0a772a4c8f311

BEACON

f7e7201325892dcc287c60a0748edb16

35f02a778ea7504331ddd025f0d927e0773ffd31

a4891cc85802833d9a89e2522a42a7e3c8dc6de1d2bbed5945497ee4006c8ddb

BEACON

c4a369880e3e5c3dc42ebf8cdacc9d6c

037889e6d714c7ff6341bdb8a8bebbddc21fc36e

756ed760cbf4b35054c78a75009f748f0f6cd5eb2cbd44bb3a2d964da3c419cf

BEACON

98f2b23eb265d73a05b2cce17d53eba4

41cc9afc79aaee60f6436192c6582907e41d89f7

87cdcbc55aed4267f47a913b17f4bc697634bf633659c639f87a4dbf00f853c1

BEACON

38667bc3ad2dcef35a5f343a5073e3f2

22cf10ec5047a86a49c1819c4943290321a29918

a8741f6f400c7fedfbdc7a298ab4a636be42d379eb4ecc3cccd81eadca09f8d0

BEACON

aa2a14e1819f4b1cc685801e07186b0d

101930bbec76ee4a147117cdfcb56aa2208a579d

5a6b7569c2b8e91f5bd8a67322af384cfad5ddaf3ea9de271093a0879b88c438

BEACON

61bbe1c1b2aa40c0d8aa7e00c2c4f7b6

6eff4b7b5ccf92eb0f134591237fe1db7c71826a

f883f7d7c068b6f1eb62804591d748c28c584fbfb769628d9567c22aa00f26f6

ROLLCOAST ransom note

July 2020

0b6757090d9ebc8d497e71b177acf256

25b175a71906e354a24003803574c4420f02a82f

e25f2284fc6e80011587bf95829d8ff30ecae06a2d2bbe494d8af3bd05f9e43f