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

Static analysis result for SHA-256 4add1cacf9f64d9c…

MALICIOUS

Office (OLE) / .XLS

201.5 KB Created: 2021-12-17 13:32:08 Authoring application: Microsoft Excel@밀糰Ǘ@䈀余Ǘ
MD5: bf2e67b6d3ee0eafc5fb49fa88e94bb6 SHA-1: dd6d305f23d6b8e5e8b60d3a9ed8b7d079e23ad8 SHA-256: 4add1cacf9f64d9cdf5e23d19d95a5404727e08ff3faa99c175219e5454be829
222 Risk Score

Malware Insights

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

The sample contains an Excel 4.0 macro sheet with an Auto_Open function, which is a known technique for executing malicious code. The macro uses dangerous functions like RUN, indicating it attempts to download and execute a payload from one of the embedded URLs. The document body also contains a lure to 'Enable Content' to view data, further supporting the malicious intent.

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/910256475912425536/921395501599948811/PEjuojHCWfAipVmerrynigga.bin
    • https://cdn.discordapp.com/attachments/910256475912425536/921395071063031878/thhBjmvULUHmerrynigga.bin
    • https://cdn.discordapp.com/attachments/910256475912425536/921394682179780608/SbcvrfsXmerrynigga.bin

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
7f5df2ed6163df8c42fea001825bc69822bc713376dd915f56bb763b94293278		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 219545 bytes

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