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

Static analysis result for SHA-256 781377cca911dc90…

MALICIOUS

Office (OOXML) / .XLSX

713.8 KB Created: 2021-08-09 02:12:21 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-02-21
MD5: f19286c90abdfea3e24de8543421e9e1 SHA-1: cbea6b192a4dd54994faebdcfc5a1bbd3d435636 SHA-256: 781377cca911dc90b76b1c01056800845efcc044165fa4cd032f9528aa9d930f
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.001 Malicious Link: Malicious Link T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking T1059 Command and Scripting Interpreter

The sample is an Excel file containing an embedded OLE object, specifically an Equation Editor object. Heuristics indicate anomalies within the Equation Editor's native stream, strongly suggesting exploitation of CVE-2018-0798. This vulnerability is known to be used for delivering malicious payloads, likely through the embedded object.

Heuristics 5

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/yNa9.FILOVWt contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
  • Heap-spray pattern detected high SC_HEAP_SPRAY
    Repeated 0x04 bytes found
  • 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
70a02587ae45028f12dc62625acbf43b5f3faa8287916e438d21b3d2553f4a09		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/yNa9.FILOVWt 1016832 bytes
ooxml_oleobject_00_ole10native_00.bin
49dea2a85c0cee02c0e554e209c995e9f65399a60ebde17b619ef6a0bd3cccae		 ole-package OOXML xl/embeddings/yNa9.FILOVWt Ole10Native stream: OLe10NAtive 1006526 bytes

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