Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 1aa21cf540ae0be2…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:34:33 Authoring application: Microsoft Excel First seen: 2021-06-20
MD5: 5c89984fc31df7b4885ba3e64c70ae24 SHA-1: 428f4d7df9a642156c59b127fa3f9b90cd42ee1a SHA-256: 1aa21cf540ae0be27133eb406513815ebc1fff91bfdb78e4938c7addbd5c7074
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. This technique is often used to automatically execute a payload when the workbook is opened. The presence of dangerous formula APIs further increases the risk. The exact nature of the payload is not discernible from the provided macro listing, but the execution mechanism is clear.

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) 6449 bytes
SHA-256: 44644259ace03247280ad7380a9b4955de3a192f22b1dd283479726b91b7b49f
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 -  cznFlJ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G186 
' 0018     25 LABEL : Cell Value, String Constant - BAnilyvHoD len=0 
' 0018     22 LABEL : Cell Value, String Constant - CmCptnF len=0 
' 0018     23 LABEL : Cell Value, String Constant - cxfypTvt len=0 
' 0018     22 LABEL : Cell Value, String Constant - GoTwRVI len=0 
' 0018     22 LABEL : Cell Value, String Constant - ncjoHao len=0 
' 0018     27 LABEL : Cell Value, String Constant - NFhKFUBzNRLw len=0 
' 0018     23 LABEL : Cell Value, String Constant - ngeLBFIR len=0 
' 0018     22 LABEL : Cell Value, String Constant - nsbRTvd len=0 
' 0018     26 LABEL : Cell Value, String Constant - NTqQlPoSIol len=0 
' 0018     26 LABEL : Cell Value, String Constant - nzQkgogWAag len=0 
' 0018     23 LABEL : Cell Value, String Constant - pVfjLHvS len=0 
' 0018     22 LABEL : Cell Value, String Constant - PznRSqE len=0 
' 0018     26 LABEL : Cell Value, String Constant - QHQFNsARzpl len=0 
' 0018     21 LABEL : Cell Value, String Constant - sCCjuI len=0 
' 0018     22 LABEL : Cell Value, String Constant - VwVkBne len=0 
' 0018     20 LABEL : Cell Value, String Constant - XRiuU len=0 
' 0018     22 LABEL : Cell Value, String Constant - XyoRAnn len=0 
' 0018     20 LABEL : Cell Value, String Constant - yrqwM len=0 
' 0018     22 LABEL : Cell Value, String Constant - YseZIMe len=0 
' 0018     23 LABEL : Cell Value, String Constant - zRmXZTng 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 LABELSS
... (truncated)

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