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

Static analysis result for SHA-256 29bf642213921602…

MALICIOUS

Office (OOXML) / .XLSX

672.6 KB Created: 2019-11-27 09:20:57 UTC Authoring application: Microsoft Excel 12.0000
MD5: 42bceb60d3f13c73291396bf8dce855e SHA-1: 1c2f3f6cb5af6a7ad2f35538323c77c1a89459ff SHA-256: 29bf642213921602445d34d9d6881d4d8b9e96da2589c8257307dc069bfc36e7
100 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 Unit Persistence T1566.001 Phishing: Spearphishing Attachment T1078.001 Valid Accounts T1078.002 Valid Accounts: Cloud Accounts

The analysis reveals an embedded OLE object containing the Equation Editor component, a known vulnerability exploited via CVE-2017-11882 and related CVEs. The presence of a malformed Ole10Native stream within this object, combined with the Equation Editor CLSID, strongly suggests a payload delivery mechanism. The file likely attempts to exploit this vulnerability to execute arbitrary code, potentially downloading and running a secondary payload. The high heuristic firing scores further support this assessment.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/KSyIb5vH.cYyw 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
86d53c337b7076d4b34e4c2a724909b7bc3beaf9f47c53231c91aa78056021e7		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/KSyIb5vH.cYyw 973312 bytes
ooxml_oleobject_00_ole10native_00.bin
3f13ae590697a2a7cfc67399179ffa02879fda3480d88e8cd87fa1a8878981ba		 ole-package OOXML xl/embeddings/KSyIb5vH.cYyw Ole10Native stream: Ole10NatIVE 963388 bytes

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