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

Static analysis result for SHA-256 3ccd695520d5a87d…

MALICIOUS

Office (OOXML) / .XLSX

756.8 KB Created: 2020-02-24 09:54:15 UTC Authoring application: Microsoft Excel 12.0000
MD5: 9481e1076f9523be78ed67af86e9154f SHA-1: 22afbb934ef70dfe1fa463e64a9bb8f04f93c0ad SHA-256: 3ccd695520d5a87d2b2070f22f228669c08cb46b148549f399e9046ae950cd9f
108 Risk Score

Malware Insights

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

The sample is an Excel file containing an embedded OLE object, specifically identified as a Equation Editor object. Heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header and a significantly larger declared size than the actual stream size, strongly suggesting exploitation of a vulnerability within the Equation Editor component. No document body text or scripts were extracted, but the presence of the anomalous OLE object points to a classic exploit delivery mechanism.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/RSLlT.ItLhDr 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
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 2 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
a08183667404a500c3b2a23e17b9201191a98af464b7a09872595c58d261f09d		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/RSLlT.ItLhDr 999936 bytes
ooxml_oleobject_00_ole10native_00.bin
ac30982e4923b9b77522251b26cf7d842636d87f16fe1233f4aa31fb1f41ac09		 ole-package OOXML xl/embeddings/RSLlT.ItLhDr Ole10Native stream: oLE10naTIVE 989467 bytes

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