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

Static analysis result for SHA-256 34b4cc54cd8d3294…

MALICIOUS

Office (OOXML) / .XLSX

2.46 MB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000
MD5: 01b22be6717e0fa7857fd6dfd8f91c18 SHA-1: 3691849757b57284826856fe2cb95e3dc5f68220 SHA-256: 34b4cc54cd8d3294a210381b7f27a9d0284214ecb26c9ad4c685a3d568d295f6
142 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 sample is an Excel file containing an embedded OLE object, specifically identified as a vulnerable Equation Editor component. Heuristics indicate an anomalous native stream within the Equation Editor object, strongly suggesting exploitation of CVE-2018-0798. This vulnerability allows for the execution of arbitrary code, likely to download and execute a secondary payload.

Heuristics 5

  • 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
  • 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
cd90110aeb9febc8c4925117f2308e12032308eff8e8b6fce017fb4b0d1a7308		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 1943040 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
c1ab729e4c039b49e4fa69770b1c685c952f5e304146ebbe457918c84dbe214b		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: ole10natiVe 1925424 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
0ff01bded64e111b28a74f685fd80b30d336b3f37fe3d43782861757a9176786		 ooxml-emf OOXML EMF part: xl/media/image6.emf 679832 bytes

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