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

Static analysis result for SHA-256 4742d662235894ea…

MALICIOUS

Office (OOXML) / .XLSX

680.9 KB Created: 2019-02-26 07:54:10 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-05-17
MD5: 7f27ca895da26b7fb71304a9037cf905 SHA-1: 6a19a428564fc19529eaa83bc11319124d7b135c SHA-256: 4742d662235894ea1a0ee5eae0b8ab667e61ccda131fe816e462b17c5409bb1e
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File T1027 Obfuscated Files or Information

The file is an Excel document containing a malicious OLE object, specifically an Equation Editor object with an anomalous Ole10Native stream. This structure strongly suggests it's designed to exploit vulnerabilities or deliver a secondary payload when opened. The document content, a Spanish purchase order, serves as a lure to trick the user into interacting with the malicious object.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/g3b9I53.tKU 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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
309143fb12f180bb0656662f1b42fb785a53ca38743fd1454d7045ef542f9251		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/g3b9I53.tKU 977408 bytes
ooxml_oleobject_00_ole10native_00.bin
3c0f0ae47b16151616f286a7af822b9e043849afab43eb5f9cc303580f64867f		 ole-package OOXML xl/embeddings/g3b9I53.tKU Ole10Native stream: oLe10NAtivE 967396 bytes

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