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

Static analysis result for SHA-256 f9ae42b3e998b7de…

MALICIOUS

Office (OOXML) / .XLSX

732.5 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-10-26
MD5: 3082bcc477192149fc388417c53bbe47 SHA-1: 488c1b847602942f952a7d7a70694d8e0429bb67 SHA-256: f9ae42b3e998b7debd5cf71113d2fea8b56c55924f0f4afd254a125422d9261e
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 Malicious Link

The file is an OOXML document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream, suggesting it's being used to exploit a known vulnerability (likely CVE-2017-11882) to execute arbitrary code. The presence of this embedded malicious object points towards a delivery mechanism for a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/CiB.mTfFA 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
60771021ff40cdee68edc89868fbfbe6284b0fd8248fc5724aaa10430ff50939		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/CiB.mTfFA 1030144 bytes
ooxml_oleobject_00_ole10native_00.bin
4cb7283af2078b7306912c35d5e0d948af455899f6e69734f93a256f80b88f23		 ole-package OOXML xl/embeddings/CiB.mTfFA Ole10Native stream: Ole10NATIVe 1019744 bytes

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