Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a1c40539e0553302…

MALICIOUS

Office (OLE)

250.0 KB Created: 2020-08-05 09:36:27 Authoring application: Microsoft Excel First seen: 2020-09-07
MD5: 4d1f0f4e77a48e56a9307a0d013e8e9d SHA-1: 35376385dda6f4d708a45a4d5442eb630b7482ff SHA-256: a1c40539e05533022624070c673002a44f1606e7794cbe56ae9c0acc011d0381
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an Excel 4.0 macro-enabled document containing an Auto_Open macro. The document body text is a lure to enable macros, claiming the document was created with an unrelated application. The XLM macro sheet contains an Auto_Open entry and uses dangerous functions, indicating it is designed to execute malicious code upon opening.

Heuristics 4

  • 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 HALT gate high OLE_XLM_ENVIRONMENT_EVASION_HALT
    Excel 4.0 macro sheet auto-executes multiple GET.WORKSPACE / GET.WINDOW environment checks and halts execution when the host does not match the expected user environment. This is a common sandbox-evasion pattern in XLM malware and is stronger than a bare XLM macro-sheet indicator.
  • 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 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 265346 bytes
SHA-256: 8ba62d6934995264418fdaa63400d52c898ef8445ead06ef02f130552662262b
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  KOOQkh
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgNameX  NAMEIDX 8 
' 0018     22 LABEL : Cell Value, String Constant - eXWdTuK len=0 
' 0018     23 LABEL : Cell Value, String Constant - GaDoZVeA len=0 
' 0018     21 LABEL : Cell Value, String Constant - GstWRJ len=0 
' 0018     25 LABEL : Cell Value, String Constant - IpyxvYLzqM len=0 
' 0018     20 LABEL : Cell Value, String Constant - JHqMc len=0 
' 0018     26 LABEL : Cell Value, String Constant - KECQlnEaUFk len=0 
' 0018     32 LABEL : Cell Value, String Constant -            hidden len=7 ptgRef3d  Sheet!D9175 
' 0018     25 LABEL : Cell Value, String Constant - MUeyHqaWLF len=0 
' 0018     22 LABEL : Cell Value, String Constant - MZeDxxy len=0 
' 0018     24 LABEL : Cell Value, String Constant - NznDaBVPc len=0 
' 0018     26 LABEL : Cell Value, String Constant - rKDwXEUEYYX len=0 
' 0018     20 LABEL : Cell Value, String Constant - sMCBi len=0 
' 0018     23 LABEL : Cell Value, String Constant - SsnrcSvx len=0 
' 0018     20 LABEL : Cell Value, String Constant - sWKRV len=0 
' 0018     22 LABEL : Cell Value, String Constant - WBHhMlF len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZeCkUXYRsU len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST :
... (truncated)