Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a6e86cde67e94dfc…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:44:02 Authoring application: Microsoft Excel First seen: 2021-09-25
MD5: d2aba70599b87734629c50d038b51e81 SHA-1: ec967751d5f8992c335bb49419b17826548cc52a SHA-256: a6e86cde67e94dfcd142bf9d2ae17c59212abad829954517338c9839421c629c
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. The critical heuristic firings indicate the presence of dangerous formula APIs within the macro, suggesting an attempt to exploit the system. The macro sheet itself contains obfuscated data, likely to hide the malicious 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: 2d77deedb89bc5ebd8cab2b66026c7b4b81ca8dd45d173542627a554c0526582
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  PpYs
' 0018     26 LABEL : Cell Value, String Constant - AneqvbKcsNs len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F178 
' 0018     26 LABEL : Cell Value, String Constant - BwpmajyrSaw len=0 
' 0018     22 LABEL : Cell Value, String Constant - dKgerZA len=0 
' 0018     20 LABEL : Cell Value, String Constant - JisGZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - JuWlgPPRnf len=0 
' 0018     26 LABEL : Cell Value, String Constant - JuYkzmBSzZK len=0 
' 0018     27 LABEL : Cell Value, String Constant - KdzSueDQjxyj len=0 
' 0018     25 LABEL : Cell Value, String Constant - KKilskZWLU len=0 
' 0018     23 LABEL : Cell Value, String Constant - kmdhgJiQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - LIQvpHp len=0 
' 0018     22 LABEL : Cell Value, String Constant - MPWYCpy len=0 
' 0018     25 LABEL : Cell Value, String Constant - OEpqpUNfjY len=0 
' 0018     22 LABEL : Cell Value, String Constant - oMMZeiO len=0 
' 0018     21 LABEL : Cell Value, String Constant - qVRmrF len=0 
' 0018     22 LABEL : Cell Value, String Constant - RPGbCLt len=0 
' 0018     26 LABEL : Cell Value, String Constant - sTJaZCZzoOl len=0 
' 0018     27 LABEL : Cell Value, String Constant - vXuHPYvEyYLN len=0 
' 0018     21 LABEL : Cell Value, String Constant - XAjhvB len=0 
' 0018     26 LABEL : Cell Value, String Constant - zgOeVwWFOTG len=0 
' 0018     22 LABEL : Cell Value, String Constant - zVJtKiF 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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