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

Static analysis result for SHA-256 15f50ba333524631…

MALICIOUS

Office (OOXML) / .XLSX

693.5 KB Created: 2023-09-27 08:05:40 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-09-29
MD5: 1c8b394dfcf617ac8e2dd5688b061669 SHA-1: c10646818f8096102fa0a9f8c220fdc0dc164bfd SHA-256: 15f50ba333524631c241aed0d3ad78d1846b2b58aea175dd98e178ae26d009de
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The file is an OOXML document containing an embedded OLE object, specifically identified as an Equation Editor. The high-severity heuristics indicate that this Equation Editor object carries a payload within its Ole10Native stream, with a declared inner size significantly larger than the stream size, suggesting potential obfuscation or a packed payload. This points to a likely exploit delivery or malware dropper mechanism.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/ewyFmrZmU.sr contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is an exploit-shaped Equation/OLE payload container seen in malicious OOXML samples. It is not assigned to a specific CVE unless the MTEF/Equation Native primitive also matches.
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
6f2181c95e421daa4cec4fe55b1e6d08723caae02860a2e67275a6ebaeba7d0d		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/ewyFmrZmU.sr 985088 bytes
ooxml_oleobject_00_ole10native_00.bin
d68f06ea63652a381dbb36b982251376dfbf482b8dcca5e7cbc3e6f28c676b52		 ole-package OOXML xl/embeddings/ewyFmrZmU.sr Ole10Native stream: ole10NaTIve 974796 bytes

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