Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b8cc0aee0e9016e8…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:44:51 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 43483b1e64d3ef3a31179918020d1311 SHA-1: 9cee95498f8770eb85c04c7415045bdca7e9d65d SHA-256: b8cc0aee0e9016e89beed2fe143aa21fe413d110b7413d283aa9538cdc45f319
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN further suggests malicious intent. While the exact payload is not clear from the truncated script, the mechanism points to a macro-based execution of arbitrary code.

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) 6649 bytes
SHA-256: 100da89b98134e96c3ba31e251b251538e820f771f5e9fcbec864f9b6cbd07c8
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  ryUInAKWRhu
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C173 
' 0018     20 LABEL : Cell Value, String Constant - cFrQW len=0 
' 0018     22 LABEL : Cell Value, String Constant - FMPciyN len=0 
' 0018     25 LABEL : Cell Value, String Constant - GvdutFYmnw len=0 
' 0018     21 LABEL : Cell Value, String Constant - JeNXFJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - jkkblnQm len=0 
' 0018     26 LABEL : Cell Value, String Constant - jVjpUKaklLF len=0 
' 0018     22 LABEL : Cell Value, String Constant - kZpJzXo len=0 
' 0018     22 LABEL : Cell Value, String Constant - LXwMrnb len=0 
' 0018     23 LABEL : Cell Value, String Constant - MAsPOkFW len=0 
' 0018     27 LABEL : Cell Value, String Constant - nqxbicqQwNpf len=0 
' 0018     24 LABEL : Cell Value, String Constant - PFzBHWoKN len=0 
' 0018     27 LABEL : Cell Value, String Constant - qgwWNVZIcUKC len=0 
' 0018     22 LABEL : Cell Value, String Constant - qJvqdOV len=0 
' 0018     25 LABEL : Cell Value, String Constant - QOmpjqdxrA len=0 
' 0018     27 LABEL : Cell Value, String Constant - sCNGuBefyGHN len=0 
' 0018     25 LABEL : Cell Value, String Constant - SUnahBZIJq len=0 
' 0018     21 LABEL : Cell Value, String Constant - tgJUGL len=0 
' 0018     22 LABEL : Cell Value, String Constant - XLhtuEq len=0 
' 0018     25 LABEL : Cell Value, String Constant - YAjosuNdTg len=0 
' 0018     23 LABEL : Cell Value, String Constant - ZDftAPCl 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
' 0
... (truncated)

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