Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 033b3e154d19975c…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:26:55 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: c3a5476dd917bc28a5d2572461df8e2e SHA-1: c72a25569b3183f820fd39efac58c185781c7ef2 SHA-256: 033b3e154d19975c08292a63e684df985614dc9ca08062fbcbed38bba000fc84
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 macros, specifically an Auto_Open function. This function is known to be used for executing malicious code, often to download and run further stages. The presence of dangerous formula APIs in the Auto_Open macro strongly suggests malicious intent. No specific URLs or hashes were extracted, but the technique itself is a high-confidence indicator of 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) 6611 bytes
SHA-256: 5e99a6c7837bdaadb8b5ff9d611045a9f68ed99d8e9fde4e024d95b4199d6abd
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 -  NvpIdZyRhQS
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C139 
' 0018     21 LABEL : Cell Value, String Constant - cmkYgS len=0 
' 0018     21 LABEL : Cell Value, String Constant - cNpfuS len=0 
' 0018     27 LABEL : Cell Value, String Constant - cVsmbTQxixYe len=0 
' 0018     27 LABEL : Cell Value, String Constant - feSczleoepwt len=0 
' 0018     21 LABEL : Cell Value, String Constant - JLkJCJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - jopIOHlx len=0 
' 0018     23 LABEL : Cell Value, String Constant - KHBmVAQY len=0 
' 0018     24 LABEL : Cell Value, String Constant - lmXIduOwd len=0 
' 0018     23 LABEL : Cell Value, String Constant - NxNlImRZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - OcKwo len=0 
' 0018     22 LABEL : Cell Value, String Constant - PezTrlz len=0 
' 0018     22 LABEL : Cell Value, String Constant - QFlhvsi len=0 
' 0018     23 LABEL : Cell Value, String Constant - QnNIlcHM len=0 
' 0018     24 LABEL : Cell Value, String Constant - rHBcbIoor len=0 
' 0018     20 LABEL : Cell Value, String Constant - tXbfF len=0 
' 0018     20 LABEL : Cell Value, String Constant - vRYIr len=0 
' 0018     24 LABEL : Cell Value, String Constant - vyCIZpXRO len=0 
' 0018     24 LABEL : Cell Value, String Constant - wgboetnCq len=0 
' 0018     26 LABEL : Cell Value, String Constant - wsYPbEJXgPW len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZFvPFtmyWYO 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 
... (truncated)

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