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

Static analysis result for SHA-256 a1c98d7ceceafd3c…

MALICIOUS

Office (OOXML) / .XLSX

604.9 KB Created: 2019-11-27 09:20:57 UTC Authoring application: Microsoft Excel 12.0000
MD5: 225f7df7078ae349995b19738f5a4ce6 SHA-1: 4e1093ae45ff81623cdffa4568c38efe3e1f97c1 SHA-256: a1c98d7ceceafd3ced14c0b2aa5ca4fccca5bdc6a52793b1951e3efcc79018be
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.001 Malicious Link: Malicious Link T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The file is an Excel spreadsheet containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header and size discrepancy, strongly suggesting exploitation of a known vulnerability like CVE-2017-11882. This technique is commonly used to download and execute a second-stage payload. No specific family could be identified, but the attack pattern is clear.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/5wIrvP.roSBP 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
1ec0e422cd919eb9661e7219217221afafb46330ad884e4a3176ae675a1982c7		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/5wIrvP.roSBP 902144 bytes
ooxml_oleobject_00_ole10native_00.bin
703356ea7e3026a7ae9daa0e4a80bde838dd49cef71f1545aed03f54c0b69050		 ole-package OOXML xl/embeddings/5wIrvP.roSBP Ole10Native stream: OLe10NATive 892828 bytes

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