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

Static analysis result for SHA-256 b62f4d81261af27c…

MALICIOUS

Office (OOXML) / .XLSX

315.9 KB Created: 2021-05-25 21:11:13 UTC Authoring application: Microsoft Excel 14.0300
MD5: f5c8c6ff728bf0de944b9d7372701bd8 SHA-1: 7bcd37ff6538b9aade7d2d6ab98a7565545158b2 SHA-256: b62f4d81261af27c2b2bed4ef5ab48701b9e52d320bc8dd031f825c0a41dfc23
100 Risk Score

Malware Insights

MITRE ATT&CK
T1071.001 Application-Specific Remote Component Execution T1566 Privilege Escalation T1059.001 Command and Scripting Interpreter

The file contains an embedded OLE object with an anomalous Equation Editor native stream, consistent with CVE-2018-0798. While the exact matrix-overflow signature is absent, the presence of the Equation Editor CLSID and the malformed native stream strongly suggests an attempt to exploit this vulnerability. The document's structure and the embedded OLE object are indicative of a downloader or payload delivery mechanism. The high confidence is based on the heuristic firings and the document excerpt's detailed analysis of the Equation Editor component.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject1.bin 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.
  • 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
0fa344aa43009737becb051c13312f67999575375a6485a9005348ac83a4a95f		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 4608 bytes
ooxml_oleobject_00_ole10native_00.bin
e74e0530d5b538102cf0ee3929f2b1282acdde4f12d05a15e965067779f3b8a0		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: ole10naTiVE 2234 bytes

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