Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 28ae241844692361…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:39:36 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 28496eb3c7465fe1d7782b83d692c5f2 SHA-1: 702ee86ef8b35d5934797be397d7213baca7de80 SHA-256: 28ae241844692361c30d4416630a63952d5106417ddd67988b8429f32f70a89e
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 function, which is a common technique for executing malicious code upon opening the document. The macro sheet contains a large amount of seemingly random data, suggesting it may be obfuscated or packed, and is likely designed to download and execute 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) 6883 bytes
SHA-256: 9cb7ea7317f22f2a8fe4b90f220e0690a6c1ef8f19cf269b615f71048b897807
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  hXwuYTHYzw
' 0018     27 LABEL : Cell Value, String Constant - ARCRqTQujRrq len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C180 
' 0018     23 LABEL : Cell Value, String Constant - BSedUmmI len=0 
' 0018     24 LABEL : Cell Value, String Constant - eMoSqFOmV len=0 
' 0018     24 LABEL : Cell Value, String Constant - epCnboHut len=0 
' 0018     20 LABEL : Cell Value, String Constant - FAPRe len=0 
' 0018     23 LABEL : Cell Value, String Constant - fgoenwMr len=0 
' 0018     27 LABEL : Cell Value, String Constant - gTCglrEyhoZg len=0 
' 0018     27 LABEL : Cell Value, String Constant - JWudEAzRYaKk len=0 
' 0018     25 LABEL : Cell Value, String Constant - klrngEesfB len=0 
' 0018     23 LABEL : Cell Value, String Constant - McKxlaGf len=0 
' 0018     21 LABEL : Cell Value, String Constant - nKMqtF len=0 
' 0018     23 LABEL : Cell Value, String Constant - PIlXRjJr len=0 
' 0018     22 LABEL : Cell Value, String Constant - sGWmERM len=0 
' 0018     21 LABEL : Cell Value, String Constant - sJuLEW len=0 
' 0018     24 LABEL : Cell Value, String Constant - SmOGcMsKC len=0 
' 0018     21 LABEL : Cell Value, String Constant - WiFVHl len=0 
' 0018     20 LABEL : Cell Value, String Constant - xQswp len=0 
' 0018     27 LABEL : Cell Value, String Constant - XwXHvhfdiRCX len=0 
' 0018     24 LABEL : Cell Value, String Constant - zbfMfPUWa len=0 
' 0018     21 LABEL : Cell Value, String Constant - zQAFip 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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