Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7a677ce6356c8d1e…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:44:07 Authoring application: Microsoft Excel First seen: 2021-07-07
MD5: dfa29a50cb4e0b2ddb7cb9d421d1e81a SHA-1: 1f27602279c769472582ce85764c70619499fccd SHA-256: 7a677ce6356c8d1eeb26760bff78bff26145f8e9d923c58698b102e3ecf9a2da
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro sheet containing an Auto_Open entry, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code or download a payload. The specific functions used are not fully detailed, but the overall pattern points to a malicious macro designed for initial execution.

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) 6701 bytes
SHA-256: 7d9fbdc729c0e988264b2f1f633a579b2f594462fc6d465e6eb54aa6878b8b3c
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 -  dxHfFjEwSNn
' 0018     25 LABEL : Cell Value, String Constant - acBtTSdLnY len=0 
' 0018     23 LABEL : Cell Value, String Constant - AOHMGKfe len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D141 
' 0018     24 LABEL : Cell Value, String Constant - cdneLByEh len=0 
' 0018     27 LABEL : Cell Value, String Constant - DWAKNedgDGrY len=0 
' 0018     20 LABEL : Cell Value, String Constant - EPCsF len=0 
' 0018     26 LABEL : Cell Value, String Constant - jOXQdskIfWI len=0 
' 0018     22 LABEL : Cell Value, String Constant - kacLqGd len=0 
' 0018     20 LABEL : Cell Value, String Constant - kHfDQ len=0 
' 0018     24 LABEL : Cell Value, String Constant - mZnqBoLph len=0 
' 0018     23 LABEL : Cell Value, String Constant - qOaNwjTE len=0 
' 0018     27 LABEL : Cell Value, String Constant - saBCTkwpjbud len=0 
' 0018     23 LABEL : Cell Value, String Constant - SFdXSoBi len=0 
' 0018     20 LABEL : Cell Value, String Constant - SKlnv len=0 
' 0018     23 LABEL : Cell Value, String Constant - SYszCgWt len=0 
' 0018     25 LABEL : Cell Value, String Constant - TyLYsClLUG len=0 
' 0018     24 LABEL : Cell Value, String Constant - vrMIeaIKL len=0 
' 0018     25 LABEL : Cell Value, String Constant - xyBKNZFHOO len=0 
' 0018     21 LABEL : Cell Value, String Constant - YwHunN len=0 
' 0018     26 LABEL : Cell Value, String Constant - yXMfuNiTUOj len=0 
' 0018     23 LABEL : Cell Value, String Constant - ZhIWduks 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
' 00
... (truncated)

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