/EternalRocks

EternalRocks worm

EternalRocks (a.k.a. MicroBotMassiveNet)

EternalRocks is a network worm (i.e. self-replicating), emerged in first half of May 2017, with oldest known sample fc75410aa8f76154f5ae8fe035b9a13c76f6e132077346101a0d673ed9f3a0dd dating to 2017-05-03. It spreads through public (The Shadow Brokers NSA dump) SMB exploits: ETERNALBLUE, ETERNALCHAMPION, ETERNALROMANCE and ETERNALSYNERGY, along with related programs: DOUBLEPULSAR, ARCHITOUCH and SMBTOUCH.

taskhost.exe properties

First stage malware UpdateInstaller.exe (got through remote exploitation with second stage malware) downloads necessary .NET components (for later stages) TaskScheduler and SharpZLib from Internet, while dropping svchost.exe (e.g. sample) and taskhost.exe (e.g. sample). Component svchost.exe is used for downloading, unpacking and running Tor from archive.torproject.org along with C&C (ubgdgno5eswkhmpy.onion) communication requesting further instructions (e.g. installation of new components).

Second stage malware taskhost.exe (Note: different than one from first stage) (e.g. sample) is being downloaded after a predefined period (24h) from http://ubgdgno5eswkhmpy.onion/updates/download?id=PC and run. After initial run it drops the exploit pack shadowbrokers.zip and unpacks contained directories payloads/, configs/ and bins/. After that, starts a random scan of opened 445 (SMB) ports on Internet, while running contained exploits (inside directory bins/) and pushing the first stage malware through payloads (inside directory payloads/). Also, it expects running Tor process from first stage to get further instructions from C&C.

Host Based indicators

Dropped files

Paths

  • c:\Program Files\Microsoft Updates\SharpZLib.zip # in newer variants

  • c:\Program Files\Microsoft Updates\svchost.exe

  • c:\Program Files\Microsoft Updates\installed.fgh

  • c:\Program Files\Microsoft Updates\ICSharpCode.SharpZipLib.dll # in newer variants

  • c:\Program Files\Microsoft Updates\Microsoft.Win32.TaskScheduler.dll

  • c:\Program Files\Microsoft Updates\SharpZLib\ # in newer variants

  • c:\Program Files\Microsoft Updates\temp\tor.zip

  • c:\Program Files\Microsoft Updates\temp\Tor\

  • c:\Program Files\Microsoft Updates\required.glo

  • c:\Program Files\Microsoft Updates\taskhost.exe

  • c:\Program Files\Microsoft Updates\TaskScheduler.zip

  • c:\Program Files\Microsoft Updates\TaskScheduler\

  • c:\Program Files\Microsoft Updates\torunzip.exe # in older variants

Persistence

  • Two scheduled tasks ServiceHost and TaskHost having multiple triggers

Scheduled tasks

Mutexes

  • {8F6F00C4-B901-45fd-08CF-72FDEFF}

  • {8F6F0AC4-B9A1-45fd-A8CF-72FDEFF}

  • 20b70e57-1c2e-4de9-99e5-69f369006912

Samples

First stage

Second stage

Network indicators

C&C server(s)

  • ubgdgno5eswkhmpy.onion

Example C&C communication

Downloading required .NET components (first stage)

  • http://api.nuget.org/packages/taskscheduler.2.5.23.nupkg
  • http://api.nuget.org/packages/sharpziplib.0.86.0.nupkg # in newer variants

Appendix

Decompilation of an older sample

  • C# source # 1ee894c0b91f3b2f836288c22ebeab44798f222f17c255f557af2260b8c6a32d

Globals

Network traffic capture (PCAP)

Yara rules

Debug strings

  • C:\Program Files (x86)\Microsoft Visual Studio\VB98\VB6.OLB

  • C:\Users\tmc\Documents\DownLoader\Project1.vbp

  • C:\Users\tmc\Documents\TorUnzip\Project1.vbp

  • c:\Users\tmc\Documents\Visual Studio 2015\Projects\MicroBotMassiveNet\taskhost\obj\x86\Debug\taskhost.pdb

  • C:\Users\tmc\Documents\Visual Studio 2015\Projects\WindowsServices\svchost\bin\svchost.pdb

Indicators of Compromise (IOC)

SHA256
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Imphash

8ef751c540fdc6962ddc6799f35a907c # older (VB6) variants of UpdateInstaller.exe

Mutexes

{8F6F00C4-B901-45fd-08CF-72FDEFF}
{8F6F0AC4-B9A1-45fd-A8CF-72FDEFF}
{8F6F0AC4-B9A1-45fd-A8CF-727220DE8F}
20b70e57-1c2e-4de9-99e5-69f369006912

File paths

c:\Program Files\Microsoft Updates\

Scheduled tasks

ServiceHost -> C:\Program Files\Microsoft Updates\svchost.exe # system start, log on, daily

TaskHost -> C:\Program Files\Microsoft Updates\taskhost.exe # system start, log on, daily