Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7fd5e7dcda8d9acc…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:43:25 Authoring application: Microsoft Excel First seen: 2021-10-01
MD5: 2255820eab73770de66eb4137dac280f SHA-1: 65d33bff22594a30a3d4a033daa9d0e2fcd75c6a SHA-256: 7fd5e7dcda8d9acc29a4d2c26b422d7abfefbc31947ef02ef9d4372aeed9d45b
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical indicator of malicious activity. The presence of dangerous formula APIs like RUN in the XLM macro suggests an attempt to execute arbitrary code. While the exact payload is not clear from the truncated macro listing, the mechanism points to a downloader or initial execution stage.

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) 6651 bytes
SHA-256: c435881d88c0f21978358ab924b2a0ccf6ad9d748a7adb98b3b91a7ced9b36c8
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  BANraqIaL
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F178 
' 0018     22 LABEL : Cell Value, String Constant - BdtYtrN len=0 
' 0018     25 LABEL : Cell Value, String Constant - CBmEJcgXdj len=0 
' 0018     21 LABEL : Cell Value, String Constant - ggVNSW len=0 
' 0018     26 LABEL : Cell Value, String Constant - JsTgkMtsusR len=0 
' 0018     22 LABEL : Cell Value, String Constant - jvKczgQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - KkHjYED len=0 
' 0018     20 LABEL : Cell Value, String Constant - OEdlg len=0 
' 0018     25 LABEL : Cell Value, String Constant - oPCQBDkuls len=0 
' 0018     22 LABEL : Cell Value, String Constant - qfSIDxL len=0 
' 0018     22 LABEL : Cell Value, String Constant - tGrEuYV len=0 
' 0018     24 LABEL : Cell Value, String Constant - TKqHzHYwY len=0 
' 0018     24 LABEL : Cell Value, String Constant - UHZWFsXfQ len=0 
' 0018     23 LABEL : Cell Value, String Constant - uokOcbHa len=0 
' 0018     23 LABEL : Cell Value, String Constant - uZijKkRG len=0 
' 0018     24 LABEL : Cell Value, String Constant - wfoUmknOG len=0 
' 0018     27 LABEL : Cell Value, String Constant - WwBPNCkgvTIE len=0 
' 0018     25 LABEL : Cell Value, String Constant - xdPUfGbeDA len=0 
' 0018     26 LABEL : Cell Value, String Constant - XhOWMTvSNEH len=0 
' 0018     25 LABEL : Cell Value, String Constant - yjmCcgvdeY len=0 
' 0018     25 LABEL : Cell Value, String Constant - YvlSzgdlaN 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
' 00
... (truncated)

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