Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fc045e7dfb5da5d5…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:39:50 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: a2cd1d254eab33551d6ce8443df77939 SHA-1: 4aa7d18cd436fd0adfe4e3c11c49fb8ca0e538d5 SHA-256: fc045e7dfb5da5d5544df31976463eec67ec1c95b4ddb5c4d604b2e654c0140e
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, which is a known method for executing malicious code upon opening the workbook. The macro sheet itself contains obfuscated data, suggesting an attempt to hide its malicious functionality. The primary function of these macros is to execute arbitrary code, likely to download and run a secondary payload.

Heuristics 3

  • 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.
  • 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) 6381 bytes
SHA-256: 0cbf833b6a897d7da96c49797fb87e8857ef48b6180c5113069936a7ebc362df
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  qxS
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A153 
' 0018     25 LABEL : Cell Value, String Constant - BDutGvgntj len=0 
' 0018     21 LABEL : Cell Value, String Constant - ByvSkP len=0 
' 0018     26 LABEL : Cell Value, String Constant - cxUKKnLqRyz len=0 
' 0018     20 LABEL : Cell Value, String Constant - dYOlK len=0 
' 0018     23 LABEL : Cell Value, String Constant - ekYzuVPS len=0 
' 0018     23 LABEL : Cell Value, String Constant - EWmnLuEN len=0 
' 0018     21 LABEL : Cell Value, String Constant - gwwZOJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - IPURIvKx len=0 
' 0018     23 LABEL : Cell Value, String Constant - kVBaaTpl len=0 
' 0018     26 LABEL : Cell Value, String Constant - LAhIiAcoHxT len=0 
' 0018     23 LABEL : Cell Value, String Constant - LXAMtAfg len=0 
' 0018     27 LABEL : Cell Value, String Constant - nlnfCUhNeeuG len=0 
' 0018     26 LABEL : Cell Value, String Constant - OZRdcooTEYh len=0 
' 0018     27 LABEL : Cell Value, String Constant - QgxBljsBxEWi len=0 
' 0018     22 LABEL : Cell Value, String Constant - TlapVMo len=0 
' 0018     23 LABEL : Cell Value, String Constant - tzNSGzhf len=0 
' 0018     27 LABEL : Cell Value, String Constant - WjjITRZUyRmg len=0 
' 0018     24 LABEL : Cell Value, String Constant - wqupqrlgv len=0 
' 0018     22 LABEL : Cell Value, String Constant - zJnrvVN len=0 
' 0018     20 LABEL : Cell Value, String Constant - ZNgEr 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     
... (truncated)

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