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

Static analysis result for SHA-256 2d987e979b47ea69…

MALICIOUS

Office (OOXML) / .XLSX

2.53 MB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000
MD5: 7969bcc49dca6aabd540bb877779e57f SHA-1: 33e95f6104d88c95431f4b4254e17417c4e760e7 SHA-256: 2d987e979b47ea6906e3582e131a522dfc0bae2b7e65aa2bd8cef5660f2ad55c
150 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.001 Malicious Link: Malicious Link T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The file contains an embedded Equation Editor OLE object that exhibits anomalies indicative of CVE-2018-0798. This object carries a payload-like Ole10Native stream, suggesting it's designed to exploit this vulnerability for initial execution. The presence of hidden worksheets further supports the concealment of malicious components.

Heuristics 6

  • 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.
  • 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
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 1 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
    URL http://www.day.com/dam/1.0
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/tiff/1.0/
    • http://purl.org/dc/elements/1.1/

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
8df4e5288bcb0492b82c06ef69d975d2837e069bc69f37100fe3ee214a1b5838		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 2056704 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.98, consistent with packed or encrypted content.
ooxml_oleobject_00_ole10native_00.bin
ed23492ddb08a006b1d8e514dbd585b43bcdb621947b9d2a786edec986a205a5		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: OLE10Native 2038097 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.
emf_00.emf
e2961c5c6c2cdfacc6749b2a8496684400349392f14382a185e78f4f12bd239f		 ooxml-emf OOXML EMF part: xl/media/image11.emf 653280 bytes

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