Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7b583451d1bc79c4…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:44:17 Authoring application: Microsoft Excel First seen: 2021-06-28
MD5: e2ad40d0c70b714db1c5a1e6ddd4ddfa SHA-1: 553358fce3adedaab9e8818f9f6998bf76756486 SHA-256: 7b583451d1bc79c48b24c8039d4aaeab070253897cabb9af63ffe09dae292778
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an Excel file containing Excel 4.0 (XLM) macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristic firings. The presence of an Auto_Open defined name suggests that the macro is designed to execute automatically when the workbook is opened. The dangerous formula APIs, specifically 'RUN', point towards the execution of external commands or payloads. This indicates a likely attack pattern of a malicious attachment delivered via spearphishing, intended to download and execute a secondary 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) 6650 bytes
SHA-256: 8204d51efe9f7400764736f199688eb12de73260596ab50bed83912ec33864c8
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 -  huMTBe
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D131 
' 0018     20 LABEL : Cell Value, String Constant - EqAuc len=0 
' 0018     23 LABEL : Cell Value, String Constant - gfkYyYOK len=0 
' 0018     21 LABEL : Cell Value, String Constant - gMSSYE len=0 
' 0018     21 LABEL : Cell Value, String Constant - iVmZCk len=0 
' 0018     24 LABEL : Cell Value, String Constant - IwqdRGGZw len=0 
' 0018     20 LABEL : Cell Value, String Constant - juHwF len=0 
' 0018     27 LABEL : Cell Value, String Constant - kEBSFCMCgMRh len=0 
' 0018     23 LABEL : Cell Value, String Constant - LHQkhgDy len=0 
' 0018     21 LABEL : Cell Value, String Constant - ojasHB len=0 
' 0018     22 LABEL : Cell Value, String Constant - oKwCirh len=0 
' 0018     24 LABEL : Cell Value, String Constant - PBCTAohoZ len=0 
' 0018     24 LABEL : Cell Value, String Constant - PVBPrrwdG len=0 
' 0018     23 LABEL : Cell Value, String Constant - RVjurklK len=0 
' 0018     26 LABEL : Cell Value, String Constant - UnXYoAneIzi len=0 
' 0018     23 LABEL : Cell Value, String Constant - uplOIidb len=0 
' 0018     26 LABEL : Cell Value, String Constant - WLfgcCpZHKi len=0 
' 0018     27 LABEL : Cell Value, String Constant - WyWetyuqrieD len=0 
' 0018     25 LABEL : Cell Value, String Constant - xWxfqDvwxs len=0 
' 0018     22 LABEL : Cell Value, String Constant - ymfPsGT len=0 
' 0018     20 LABEL : Cell Value, String Constant - yokCk 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 LABE
... (truncated)