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

Static analysis result for SHA-256 1f943b9381490f9e…

MALICIOUS

Office (OOXML) / .XLSX

731.9 KB Created: 2021-08-09 02:12:21 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-07-04
MD5: 3416e00d133202c9205310f28196fbd7 SHA-1: 6377c147f6e9aa6ba7a17a4ace1baf188e7e59fa SHA-256: 1f943b9381490f9e85fc6af3d033d5a42d66a8df3fceca51d65e33eaa61117b9
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1027 Obfuscated Files or Information

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 execute a payload. The embedded OLE object itself is large and exhibits high entropy, further supporting its role as a carrier for malicious code.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/vjmOk.e3G0Y 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
8a23c6dbd60944bb10f62c3543ec735498dac8f4c592eca6d7898d4868f0540a		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/vjmOk.e3G0Y 998912 bytes
ooxml_oleobject_00_ole10native_00.bin
88d72ee6b69fd067118998f58ae21e350003f5fbf62a8d542bed6177423a49ce		 ole-package OOXML xl/embeddings/vjmOk.e3G0Y Ole10Native stream: OLE10NatiVE 988559 bytes

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