Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 0bf565ca943c5ca8…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:43:18 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 834a2a9eb3e7077230b028b930e036de SHA-1: 091cd6ac846e64cbf833b6b8c35fdc7c39b09d34 SHA-256: 0bf565ca943c5ca807d69652e5b131eb8e7ff533ee96bb8e99945947c7a2ec56
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, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_AUTOOPEN_DEFINEDNAME heuristics. The OLE_XLM_DANGEROUS_FN heuristic specifically flags the use of dangerous functions within the Auto_Open macro, such as RUN=0, which is commonly used to execute arbitrary code. This suggests the macro is 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) 6490 bytes
SHA-256: 56fe3b589bd57298dec86375e32b2a8ec7e90ef9e257f8ac131f3878ab8fd177
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 -  AceIIo
' 0018     27 LABEL : Cell Value, String Constant - ANmroRCFkLVd len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I195 
' 0018     21 LABEL : Cell Value, String Constant - cKpYry len=0 
' 0018     27 LABEL : Cell Value, String Constant - dlASJufqnUar len=0 
' 0018     23 LABEL : Cell Value, String Constant - fecXQnCk len=0 
' 0018     20 LABEL : Cell Value, String Constant - fUTOj len=0 
' 0018     22 LABEL : Cell Value, String Constant - gmTwyZc len=0 
' 0018     20 LABEL : Cell Value, String Constant - GQqho len=0 
' 0018     23 LABEL : Cell Value, String Constant - iezZIaHt len=0 
' 0018     24 LABEL : Cell Value, String Constant - jhMMiRVRo len=0 
' 0018     22 LABEL : Cell Value, String Constant - JLTspzU len=0 
' 0018     20 LABEL : Cell Value, String Constant - KQTKM len=0 
' 0018     27 LABEL : Cell Value, String Constant - MNFjzoypbPdj len=0 
' 0018     27 LABEL : Cell Value, String Constant - OBWmUwkAMVcm len=0 
' 0018     24 LABEL : Cell Value, String Constant - PemJsKSoz len=0 
' 0018     25 LABEL : Cell Value, String Constant - PpPBOzffPv len=0 
' 0018     22 LABEL : Cell Value, String Constant - snvoKsS len=0 
' 0018     25 LABEL : Cell Value, String Constant - ThBLXslvYF len=0 
' 0018     27 LABEL : Cell Value, String Constant - uXGTOTNYVuEE len=0 
' 0018     22 LABEL : Cell Value, String Constant - wSLUySM len=0 
' 0018     26 LABEL : Cell Value, String Constant - zVvArCIgpnG 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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