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

Static analysis result for SHA-256 92a12d4b1d426034…

MALICIOUS

Office (OOXML) / .XLSX

778.7 KB Created: 2020-08-20 17:59:18 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-11-02
MD5: a4effa0610e49afa9cee7516127ecbf8 SHA-1: ee5bf7b57cf721902d77dd2ec32ae180652a535f SHA-256: 92a12d4b1d426034d1f224e308844dd6602eaf5ead5f4492bc9e0b868a61e7bd
108 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 User Execution: Malicious File

The sample is an XLSX file containing an embedded OLE object, specifically an Equation Editor object. Heuristics indicate this object carries a payload-like stream with an anomalous header and a significantly larger declared inner size than the stream size, suggesting it's packed or obfuscated. The document body contains invoice-like text, aligning with the 'Fake invoice / payment lure' heuristic. This combination strongly suggests the embedded object is intended to be executed, likely leading to a second-stage payload download or execution.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/gv.eZ contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • 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
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
090480e99c79d347b103d8ded8b3e8b3e97b33c8596510796049cc54afa0ef58		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/gv.eZ 987648 bytes
ooxml_oleobject_00_ole10native_00.bin
eb8af006da7862172781f980375feb5618be6d7e79eac1f8cbca2781d3bc325b		 ole-package OOXML xl/embeddings/gv.eZ Ole10Native stream: ole10NatIVe 977199 bytes

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