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

Static analysis result for SHA-256 4e52766fa90e1ffd…

MALICIOUS

Office (OOXML) / .XLSX

849.4 KB Created: 2023-01-19 05:24:18 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-06-12
MD5: ca2c4733c657dc8a1c66507f14f62970 SHA-1: c2c049e161bd514eda1f278114de5e1fdaaeba9a SHA-256: 4e52766fa90e1ffd16cba2eb039e5bdb2916f2c6d61d3f53461f44b4e9796907
140 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 vulnerable Equation Editor component. Heuristics indicate anomalies consistent with CVE-2018-0798, suggesting the Equation Editor object is used to carry a malicious payload. This points to an attack pattern leveraging a known vulnerability for initial compromise.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/FsRl.UO 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
3a332887630ffa640842924d432cd9fbaac733a8af4dd52db30f37ce56c5a54c		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/FsRl.UO 1106432 bytes
ooxml_oleobject_00_ole10native_00.bin
247e9707506a41e69465ef6bd863d4323359bc3d4ee84d8def11418d6b3ccfaf		 ole-package OOXML xl/embeddings/FsRl.UO Ole10Native stream: oLE10NatIVE 1095620 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.