Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 b5575d74de9bc55e…

MALICIOUS

Office (OOXML)

639.6 KB Created: 2019-11-27 09:20:57 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2021-06-17
MD5: ba87bf76a03ee1f5892078dfcdc189eb SHA-1: 33497955196bdd10dad38d63f24083ada599e647 SHA-256: b5575d74de9bc55e1e1df6e01e8599c64822050e86bc3eddfee2edc28cf2fa8c
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this object carries a payload-like Ole10Native stream with an anomalous header and a significantly larger declared inner size than the stream size, strongly suggesting exploitation of a vulnerability within the Equation Editor. This technique is commonly used to execute arbitrary code, likely leading to the download and execution of a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/C86X6uRi7.8nfi5BA 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 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/C86X6uRi7.8nfi5BA 942592 bytes
SHA-256: c0093a5180ca6339ade1a02e30432bf60700291638181938f851d215b5a88fb9
ooxml_oleobject_00_ole10native_00.bin ole-package OOXML xl/embeddings/C86X6uRi7.8nfi5BA Ole10Native stream: oLe10NativE 932764 bytes
SHA-256: 3feb9d79bb3211d9b9cd62f9510697a7a4b1bd7e7f277b5b422215da0d93bc41

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