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

Static analysis result for SHA-256 2199f67e89fdaa5a…

MALICIOUS

Office (OLE) / .XLSX

171.5 KB Created: 2021-10-27 10:31:49 Authoring application: Microsoft Excel
MD5: b2e024279aad600fcdabcded048c7f50 SHA-1: 785a4d8d86ae4dadf7d2d1389ad522b243fb42e1 SHA-256: 2199f67e89fdaa5a3848f2fad123d463bafcd203324318574540896196234641
202 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros, specifically an Auto_Open macro that utilizes dangerous functions like RUN. The macro attempts to execute a command-line process, specifically 'wmic process call create "C:\ProgramData\WakpARmhK.rtf"', which is likely a second-stage payload. One of the extracted URLs, http://149.129.254.152:8080/6tfcnfucknugget4gpenis3dade5z6cpc, is likely associated with the payload delivery.

Heuristics 5

  • 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 (4 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.
  • 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 http://149.129.254.152:8080/6tfcnfucknugget4gpenis3dade5z6cpc
    • https://cdn.discordapp.com/attachments/911246617275957290/915526473467719720/KsXtuXmxoZvgudVwhoreniggagay.bin
    • https://cdn.discordapp.com/attachments/911246617275957290/915526468073848872/xTpcaEZvwmHqwhoreniggagay.bin
    • https://cdn.discordapp.com/attachments/911246617275957290/915526461379727370/GYRxsMXKtvwSwhoreniggagay.bin

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
b09de5bd1e36957b10e42f30dd9f5dde5ca35321718d5778348d9dac6dd1a937		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2068 bytes

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