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

Static analysis result for SHA-256 c1158a1df03d7585…

MALICIOUS

Office (OOXML) / .XLSX

1.02 MB Created: 2022-11-18 02:05:27 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-03-10
MD5: afd2e15a47dc9394c96f5e83078ea288 SHA-1: b17977343c32004cc7e2f692fd04ee0ec3bea0b5 SHA-256: c1158a1df03d75859f08f5e9f8909ea8bf5c63a6dbc78485d543dfa461cfe478
140 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

The sample is an Excel file containing an embedded OLE object, specifically an Equation Editor object. High-severity heuristics indicate that this Equation Editor object is anomalous and carries a payload, strongly suggesting exploitation of CVE-2018-0798. This technique is commonly used to download and execute a second-stage payload.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/l8Jt4.QU 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.
  • 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
906e4651628d9f8ee97474319c4bacc7868d61ae61f3d37a9f8edc7b483a4089		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/l8Jt4.QU 1382400 bytes
ooxml_oleobject_00_ole10native_00.bin
a686ec3c521ddd6bd9627010c7d57bd5e10462bca2aab243c5bdad59d71c6f21		 ole-package OOXML xl/embeddings/l8Jt4.QU Ole10Native stream: oLE10NatIve 1368747 bytes

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