Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 5de9a2fb4b9a65e5…

MALICIOUS

Office (OLE) / .XLS

143.0 KB Created: 2021-12-16 12:35:27 Authoring application: Microsoft Excel@醀束Ǘ@ᒀ缹Ǘ
MD5: 25c49a2d3df43e919df3dbd27cd07745 SHA-1: f5997183101be768c68d53f078ad4a192201a0eb SHA-256: 5de9a2fb4b9a65e5b48d78ed6a09e6cbdca07d30e917b5777be56d7c2e7acc0e
222 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File

This Excel 4.0 macro-enabled spreadsheet contains an Auto_Open macro that uses dangerous formula APIs, including the RUN function. The document body prompts the user to 'Enable Content to edit form', indicating a lure to bypass security measures. The macro is designed to download and execute a second-stage payload from one of the three embedded URLs.

Heuristics 6

  • 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.
  • URL reconstructed from XLM cell array (3 URLs) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://cdn.discordapp.com/attachments/910215086298247232/921000519361777684/FgrHlNXpNLZchristmasnigga.bin
    • https://cdn.discordapp.com/attachments/910215086298247232/921000540345864192/KPPDYLMpIRTZchristmasnigga.bin
    • https://cdn.discordapp.com/attachments/910213738685145093/921001551454142494/GwKdPknSekFchristmasnigga.bin

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
1f31d15b08a35cb6df74d9b33c334a26fa0f78dba28e540afcea71c43fc491b3		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 4881 bytes

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