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

Static analysis result for SHA-256 cdcaf52cd77bcf04…

MALICIOUS

Office (OOXML) / .XLSX

8.9 KB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000
MD5: a000afb7e991415c9160e57ad0f47d33 SHA-1: ecf627afa01e4570ab62f81523305400471b61b0 SHA-256: cdcaf52cd77bcf0482b80849fc807f1681ef120fc0f9dbe15ae6dbb184511020
100 Risk Score

Malware Insights

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

The sample is an Office Open XML spreadsheet containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate an anomaly in the Equation Editor's native stream, strongly suggesting exploitation of CVE-2018-0798. This vulnerability allows for arbitrary code execution, likely to download and execute a second-stage payload. No scripts or document body text were extracted, limiting further analysis of the payload's nature.

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
5f830f36e2e8cfcf429a6466af8d2b024bee97a1e83b8776621d093346bbb088		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 4096 bytes
ooxml_oleobject_00_ole10native_00.bin
be67aa79389bd469da5a3aad0edf1fe2392229f69a01f843b3267534e2461dc2		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10NATIVe 1583 bytes

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