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

Static analysis result for SHA-256 85f471e81a30470e…

MALICIOUS

Office (OOXML) / .XLSX

632.4 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-09-21
MD5: 11a555aac8b3f7cf6909514059bde8cd SHA-1: fe0d334cc8d8feddb5391495fc4054ed2a29e946 SHA-256: 85f471e81a30470e108b7cdd81400b3716232d89e855e2484376dae63f91b752
100 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking

The sample is an OOXML file containing an embedded OLE object identified as an Equation Editor. This object carries a payload-like Ole10Native stream with an anomalous header and a significantly larger declared inner size than the actual stream size, indicating potential obfuscation or a packed payload. This technique is commonly used to deliver second-stage malware.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/ICiI82T.Dq6X 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
55810a60c8f7194176bdb04767d2398b424307aeee93d86764e5b3733aaa262d		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/ICiI82T.Dq6X 924160 bytes
ooxml_oleobject_00_ole10native_00.bin
904e63a5469b84b183c8195fb9fdf1864e2045a317ed285f9c42595425db2bf1		 ole-package OOXML xl/embeddings/ICiI82T.Dq6X Ole10Native stream: olE10NAtivE 914301 bytes

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