Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 74c6635afb5f71d4…

MALICIOUS

Office (OLE)

259.5 KB Created: 2020-06-24 17:08:55 Authoring application: Microsoft Excel First seen: 2020-09-07
MD5: 3ef913578008d513c043b43fbf7af2fe SHA-1: e5d257e81051c5a84436a362264a499a260deee0 SHA-256: 74c6635afb5f71d4287d0a7d395fb520aa2bf2270db94fc5e803e36915adaec5
280 Risk Score

Malware Insights

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

The file contains critical heuristic firings indicating the presence of Excel 4.0 macros with Auto_Open functionality, dangerous API usage, and environment evasion. ClamAV also detected it as 'Xls.Dropper.Agent-8915391-0'. The XLM macros are designed to execute and likely download a second-stage payload, as suggested by the 'RUN' API usage and the dropper classification.

Heuristics 6

  • ClamAV: Xls.Dropper.Agent-8915391-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-8915391-0
  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • XLM Auto_Open environment-evasion close gate critical OLE_XLM_ENVIRONMENT_EVASION_CLOSE
    Excel 4.0 macro sheet auto-executes environment checks with GET.WORKSPACE / GET.WINDOW, then shows a fake corruption/error message and closes the workbook when the host fails those checks. This is a malware sandbox-evasion pattern, even when the later payload stage is hidden behind obfuscated defined-name flow.
  • 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.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

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) 116475 bytes
SHA-256: f76bc7d6925457deb0bf0a6eba91101a1d61ad2327273ed62ae2384befb8b135
Preview script
First 1,000 lines of the extracted script
' 0085      9 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  
' 0085     18 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 
' 0085     18 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 
' 0085     19 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -  XzgxkoOozt
' 0085     18 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 
' 0085     18 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 
' 0085     18 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 
' 0085     18 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 
' 0085     18 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 
' 0085     18 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     20 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, hidden -    8 A
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0018     20 LABEL : Cell Value, String Constant - BcyxZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - BgppoteX len=0 
' 0018     21 LABEL : Cell Value, String Constant - BVxDQN len=0 
' 0018     20 LABEL : Cell Value, String Constant - cDoFI len=0 
' 0018     22 LABEL : Cell Value, String Constant - CZgnRed len=0 
' 0018     21 LABEL : Cell Value, String Constant - Dirrpu len=0 
' 0018     21 LABEL : Cell Value, String Constant - dTyIIH len=0 
' 0018     24 LABEL : Cell Value, String Constant - DwPMiFdVR len=0 
' 0018     20 LABEL : Cell Value, String Constant - eJWVl len=0 
' 0018     21 LABEL : Cell Value, String Constant - eqTmSp len=0 
' 0018     22 LABEL : Cell Value, String Constant - eVMZjTS len=0 
' 0018     29 LABEL : Cell Value, String Constant - FtOFvJTCCpbDZl len=0 
' 0018     24 LABEL : Cell Value, String Constant - fzqhuFnnb len=0 
' 0018     20 LABEL : Cell Value, String Constant - GExQN len=0 
' 0018     23 LABEL : Cell Value, String Constant - GGhpCexd len=0 
' 0018     20 LABEL : Cell Value, String Constant - gZgLX len=0 
' 0018     23 LABEL : Cell Value, String Constant - htifZroL len=0 
' 0018     24 LABEL : Cell Value, String Constant - huJpItxXL len=0 
' 0018     22 LABEL : Cell Value, String Constant - HWdfoMH len=0 
' 0018     24 LABEL : Cell Value, String 
... (truncated)
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 717 bytes
SHA-256: be23b65a6fa29680599137f837eec0639785801749f6f7877198f0531b8d3b52
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module1"
Sub RectangleRoundedCorners5_Click()
    Selection.Font.Bold = True
End Sub

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

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