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

Static analysis result for SHA-256 28b8cffcdb66f205…

MALICIOUS

Office (OOXML) / .XLSX

597.2 KB Created: 2010-06-04 08:55:28 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-09-29
MD5: 51cb52e90364510a29a30a49763a3580 SHA-1: bee76d9aff0be7f787e9a1121be500434503ffcf SHA-256: 28b8cffcdb66f2059003365c5acb5cdad53a037e8a8e0cc5f942b2e1826d34c9
100 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1204.002 Malicious File

The sample is an Excel file containing an embedded OLE object, specifically identified as an Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream, suggesting it's being used to exploit a vulnerability. The large declared inner size compared to the stream size further supports this, pointing towards a potential buffer overflow or similar exploit. The embedded OLE object is the primary indicator of malicious activity.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/B23.pYS 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
eaa31657ff29305f3b8688d3ead13c261f70937b767f6fc7532a7ff31a4203c2		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/B23.pYS 796672 bytes
ooxml_oleobject_00_ole10native_00.bin
d3435715bed54f3bceefce60d78a47a8bb3e0d64ffc069ca5960dbadbe1d537b		 ole-package OOXML xl/embeddings/B23.pYS Ole10Native stream: oLE10naTIvE 787839 bytes

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