Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e7a5a30188aefef4…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:43:25 Authoring application: Microsoft Excel First seen: 2021-07-02
MD5: f7d3d5f6d66052e1a3c9b8b65fe8827f SHA-1: 81012b6c0885ec2189c309ceaa45f4ca97474df9 SHA-256: e7a5a30188aefef49709c66d0292e241d0df8892bcefcd8c8032b439df874adb
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 defined name, which is a critical finding indicating potential automatic execution of malicious code upon opening the workbook. The presence of dangerous formula APIs like RUN further increases the risk. The macro sheet itself contains a large amount of obfuscated data, suggesting it is designed to hide its true functionality, likely to download and execute a second-stage 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) 6608 bytes
SHA-256: 61d49883cb5f12e7f8a83961a465f3eecd015024835403deb2d9eed9f0d90f4f
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 -  wRRNssWvCuf
' 0018     24 LABEL : Cell Value, String Constant - AbfiLoPPv len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G149 
' 0018     20 LABEL : Cell Value, String Constant - cthWO len=0 
' 0018     21 LABEL : Cell Value, String Constant - eWCwkn len=0 
' 0018     23 LABEL : Cell Value, String Constant - eYatjrzR len=0 
' 0018     23 LABEL : Cell Value, String Constant - GCsDnsUE len=0 
' 0018     26 LABEL : Cell Value, String Constant - GqnhHyBJQjM len=0 
' 0018     21 LABEL : Cell Value, String Constant - iojDnM len=0 
' 0018     21 LABEL : Cell Value, String Constant - IrxsiT len=0 
' 0018     23 LABEL : Cell Value, String Constant - JrkXcSMo len=0 
' 0018     21 LABEL : Cell Value, String Constant - KhJZxN len=0 
' 0018     27 LABEL : Cell Value, String Constant - kvNUWpmcQSLB len=0 
' 0018     25 LABEL : Cell Value, String Constant - ofjspxesYG len=0 
' 0018     21 LABEL : Cell Value, String Constant - orJtEP len=0 
' 0018     27 LABEL : Cell Value, String Constant - PDvaWxbIoeev len=0 
' 0018     22 LABEL : Cell Value, String Constant - pOJdUsO len=0 
' 0018     20 LABEL : Cell Value, String Constant - QDmPp len=0 
' 0018     24 LABEL : Cell Value, String Constant - qiITcbtHa len=0 
' 0018     22 LABEL : Cell Value, String Constant - rnsIhuK len=0 
' 0018     23 LABEL : Cell Value, String Constant - uOKCGigW len=0 
' 0018     22 LABEL : Cell Value, String Constant - vTBpnTU 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 LABEL
... (truncated)

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