Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fbb19458e1b3501d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:39:10 Authoring application: Microsoft Excel First seen: 2021-06-28
MD5: c16ce505d8726aac6620e5fcd5fee6d7 SHA-1: 3926368402954720f9cfc41cb632da9f682ae575 SHA-256: fbb19458e1b3501d0fc44e9af5bfe0e785fb01d3ff81210fed8dcb4971ccd319
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 defined name, which is a common technique for executing malicious code. The macro sheet contains formulas that leverage dangerous APIs, suggesting an intent to execute arbitrary commands or download further payloads. The specific formulas used are not fully detailed, but the Auto_Open entry is a strong indicator of malicious intent.

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) 6633 bytes
SHA-256: fc0ca3dd7df54381cfbbd0aa6b7ce41788519c8adf2218d0d908a933d271aaf0
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 -  Buvukx
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H176 
' 0018     21 LABEL : Cell Value, String Constant - cmpSuI len=0 
' 0018     20 LABEL : Cell Value, String Constant - DKqsi len=0 
' 0018     24 LABEL : Cell Value, String Constant - DPRMRNKVb len=0 
' 0018     24 LABEL : Cell Value, String Constant - fCnctWhDj len=0 
' 0018     27 LABEL : Cell Value, String Constant - GOaGxAGayxtB len=0 
' 0018     26 LABEL : Cell Value, String Constant - GYaXmHmStKL len=0 
' 0018     26 LABEL : Cell Value, String Constant - GYqhBRPEUQs len=0 
' 0018     20 LABEL : Cell Value, String Constant - jECQm len=0 
' 0018     22 LABEL : Cell Value, String Constant - JlxjLdO len=0 
' 0018     22 LABEL : Cell Value, String Constant - jPQlBjs len=0 
' 0018     24 LABEL : Cell Value, String Constant - KyjqnyYxN len=0 
' 0018     20 LABEL : Cell Value, String Constant - LbyPL len=0 
' 0018     25 LABEL : Cell Value, String Constant - lHDQfJtcpk len=0 
' 0018     23 LABEL : Cell Value, String Constant - qxYtoNjt len=0 
' 0018     20 LABEL : Cell Value, String Constant - SBAZE len=0 
' 0018     22 LABEL : Cell Value, String Constant - TbfYKnS len=0 
' 0018     24 LABEL : Cell Value, String Constant - UCBJpuvKq len=0 
' 0018     24 LABEL : Cell Value, String Constant - VnvRomzje len=0 
' 0018     21 LABEL : Cell Value, String Constant - WvHIYz len=0 
' 0018     24 LABEL : Cell Value, String Constant - ZyHcNlPdO 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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