Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 113efc6a557ecc44…

MALICIOUS

Office (OLE)

37.0 KB Created: 2020-11-25 10:39:40 Authoring application: Microsoft Excel First seen: 2021-11-03
MD5: 6dbd1c5395e22de04daa5b9e682aab78 SHA-1: 11f401052bb6b39eede4610ab1d545176cf203e2 SHA-256: 113efc6a557ecc443de4f68f6703f9bf69d34b4fbd2e438490ef76c63dd29462
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro sheet, identified by the presence of an Auto_Open defined name and the use of dangerous formula APIs. This indicates the macro will execute automatically upon opening the workbook. The macro sheet contains a large amount of obfuscated data and truncated script content, suggesting it is designed to download and execute a secondary payload. The specific nature of the payload cannot be determined from the provided evidence.

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) 6488 bytes
SHA-256: ddaab00d22062bdb46c68c7b81095211b4762693c8d8e476669dd2e54f8a36f1
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  RYAK
' 0018     24 LABEL : Cell Value, String Constant - AKjiFhFzG len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A138 
' 0018     25 LABEL : Cell Value, String Constant - cDNgfyftnw len=0 
' 0018     26 LABEL : Cell Value, String Constant - CSShUvhxSgk len=0 
' 0018     21 LABEL : Cell Value, String Constant - DbGirI len=0 
' 0018     22 LABEL : Cell Value, String Constant - FBpwBEe len=0 
' 0018     22 LABEL : Cell Value, String Constant - fsJYmNW len=0 
' 0018     21 LABEL : Cell Value, String Constant - gfJzwb len=0 
' 0018     21 LABEL : Cell Value, String Constant - IZSAHv len=0 
' 0018     27 LABEL : Cell Value, String Constant - JrQabaGQieRv len=0 
' 0018     22 LABEL : Cell Value, String Constant - kyseEaj len=0 
' 0018     23 LABEL : Cell Value, String Constant - mgUwsCSf len=0 
' 0018     21 LABEL : Cell Value, String Constant - mUMSPJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - oDhbEa len=0 
' 0018     25 LABEL : Cell Value, String Constant - ojIpUQhlTe len=0 
' 0018     25 LABEL : Cell Value, String Constant - rawCYXpuWq len=0 
' 0018     27 LABEL : Cell Value, String Constant - RpnAhBjTgruk len=0 
' 0018     20 LABEL : Cell Value, String Constant - vHZmL len=0 
' 0018     25 LABEL : Cell Value, String Constant - YoHXUzQQTF len=0 
' 0018     25 LABEL : Cell Value, String Constant - zabUevfXCN len=0 
' 0018     20 LABEL : Cell Value, String Constant - ZOBoD 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 LABEL
... (truncated)

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