Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 c64b9e04c85f5e2a…

MALICIOUS

Office (OOXML)

17.5 KB Created: 2020-09-11 04:19:15 UTC Authoring application: Microsoft Excel 14.0300 First seen: 2020-10-09
MD5: e13853c9632825943b6a1391c652af13 SHA-1: dad15f21de6d8338d36d1a1754a6a428c53bb48f SHA-256: c64b9e04c85f5e2a13949dcad460666f952816ad2ffa646febb73abfc905c97d
168 Risk Score

Heuristics 5

  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • PowerShell reference in VBA critical OLE_VBA_PS
    PowerShell reference in VBA
    Matched line in script
        Action.Path = "powershell.exe"
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
        Set service = CreateObject("Schedule.Service")
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Triggers on the COMBINATION of two tokens co-occurring in the same compiled VBA/cache stream: an auto-execution entry point (Auto_Open / AutoOpen / Document_Open / Workbook_Open / Auto_Close / AutoClose) AND a shell/download/object-execution token (Shell, CreateObject, GetObject, PowerShell, cmd.exe, URLDownloadToFile, WinHttp, XMLHTTP, ADODB.Stream, ShellExecute, ExecuteExcel4Macro). Neither token alone fires it — it is the pairing that flags p-code-only or source-extraction-failure macro documents where the visible VBA source is unavailable. The matched tokens are named in the detail line below.
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Private Sub Workbook_Open()

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 3101 bytes
SHA-256: d2f1ec4a2e711727b059851f80ee6654c1c8ca8fb5bf98018d172e3fa43e86cd
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 Sub Workbook_Open()
    Set service = CreateObject("Schedule.Service")
    Call service.Connect

    Dim rootFolder
    Set rootFolder = service.GetFolder("\")

    Dim taskDefinition
    Set taskDefinition = service.NewTask(0)

    Dim regInfo
    Set regInfo = taskDefinition.RegistrationInfo
    regInfo.Description = "Start notepad at a certain time"
    regInfo.Author = "Author Name"

    Dim principal
    Set principal = taskDefinition.principal

    ' Set the logon type to interactive logon
    principal.LogonType = 3

    Dim settings
    Set settings = taskDefinition.settings
    settings.Enabled = True
    settings.StartWhenAvailable = True
    settings.Hidden = False

    Dim triggers
    Set triggers = taskDefinition.triggers

    Dim trigger
    Set trigger = triggers.Create(1)

    Dim startTime, endTime

    Dim time
    time = DateAdd("s", 4, Now)
    startTime = XmlTime(time)

    time = DateAdd("s", 10, Now)
    endTime = XmlTime(time)
    
    trigger.StartBoundary = startTime
    trigger.EndBoundary = endTime
    trigger.ExecutionTimeLimit = "PT5M"
    trigger.ID = "TimeTriggerId"
    trigger.Enabled = True

    Dim Action
    Set Action = taskDefinition.Actions.Create(0)
    Action.Path = "powershell.exe"
    
    Call rootFolder.RegisterTaskDefinition( _
        "Test TimeTrigger", taskDefinition, 6, , , 3)
End Sub

Function XmlTime(t)
    Dim cSecond, cMinute, CHour, cDay, cMonth, cYear
    Dim tTime, tDate

    cSecond = "0" & Second(t)
    cMinute = "0" & Minute(t)
    CHour = "0" & Hour(t)
    cDay = "0" & Day(t)
    cMonth = "0" & Month(t)
    cYear = Year(t)

    tTime = Right(CHour, 2) & ":" & Right(cMinute, 2) & _
        ":" & Right(cSecond, 2)
    tDate = cYear & "-" & Right(cMonth, 2) & "-" & Right(cDay, 2)
    XmlTime = tDate & "T" & tTime
End Function

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 = "Sheet2"
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 = "Sheet3"
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
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 25088 bytes
SHA-256: 5b421c6f9a17782bb02d8d365d0d491feebf81cb3dd93f4ee11a325a4799f079

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