Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 1d8408eb9ee03a97…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:45:37 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: f2cc4812da526e8158c9cda5cd001a16 SHA-1: 94127e60bfd3dae7df2abc4c740f43b632e0da49 SHA-256: 1d8408eb9ee03a971c33994360fe9124df1976de5522abaec0863423eaf8fb33
140 Risk Score

Malware Insights

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

The critical OLE_XLM_AUTOOPEN_DEFINEDNAME and OLE_XLM_DANGEROUS_FN heuristics indicate the presence of an Excel 4.0 macro sheet with an Auto_Open entry that utilizes dangerous formula APIs. This strongly suggests the file is designed to execute arbitrary code when opened, likely to download and run 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) 6576 bytes
SHA-256: 7be2fbc492da31c5bf9bd913e5e4e49b3f499141f97b360761e0cd38df43cafc
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  lnoOLbU
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E177 
' 0018     25 LABEL : Cell Value, String Constant - bRMhGyLOJL len=0 
' 0018     25 LABEL : Cell Value, String Constant - dwQPewhyGd len=0 
' 0018     24 LABEL : Cell Value, String Constant - eYJfJyaBa len=0 
' 0018     24 LABEL : Cell Value, String Constant - FMbfdoaXQ len=0 
' 0018     27 LABEL : Cell Value, String Constant - gluAekfGpKuS len=0 
' 0018     27 LABEL : Cell Value, String Constant - HSxssOvJUhLR len=0 
' 0018     23 LABEL : Cell Value, String Constant - kbMcjIEr len=0 
' 0018     21 LABEL : Cell Value, String Constant - kkGlDs len=0 
' 0018     22 LABEL : Cell Value, String Constant - lMPmbIu len=0 
' 0018     23 LABEL : Cell Value, String Constant - PBUEKkZf len=0 
' 0018     27 LABEL : Cell Value, String Constant - pYksfojpBMKv len=0 
' 0018     24 LABEL : Cell Value, String Constant - QzBrifICl len=0 
' 0018     27 LABEL : Cell Value, String Constant - RuliVFKOWhUe len=0 
' 0018     25 LABEL : Cell Value, String Constant - RuWksyFzCx len=0 
' 0018     25 LABEL : Cell Value, String Constant - uvKpoCEBSO len=0 
' 0018     26 LABEL : Cell Value, String Constant - UwaypFGTNdb len=0 
' 0018     24 LABEL : Cell Value, String Constant - YmppEJzQt len=0 
' 0018     25 LABEL : Cell Value, String Constant - ytBkDKszpI len=0 
' 0018     22 LABEL : Cell Value, String Constant - zNEdGSG len=0 
' 0018     26 LABEL : Cell Value, String Constant - zOpZzXjoJdf 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 C
... (truncated)

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