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

Static analysis result for SHA-256 28626521daead15f…

MALICIOUS

Office (OOXML) / .XLSX

673.7 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-10-24
MD5: 5561ef60269bfbcad87ec744dad5863c SHA-1: 5f889f21af0d87dd0662bdaea1b55705c87da7c2 SHA-256: 28626521daead15f9a1525aad7ac09be7cd13cdc4fa3c8e05cfca1a2474460fb
100 Risk Score

Malware Insights

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

The XLSX file contains an embedded OLE object, specifically identified as a Microsoft Equation Editor object. This object exhibits an anomaly where the Ole10Native stream appears to contain a payload, indicated by an impossible header and a significant size discrepancy. This strongly suggests the exploitation of a known vulnerability within the Equation Editor to deliver a secondary malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/QVSw.tJd5qw 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
72289f035fdca4fa21de1efd5f48f034a5462df15ed308348aa9c7ce0c7b3110		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/QVSw.tJd5qw 1012224 bytes
ooxml_oleobject_00_ole10native_00.bin
fd890a616674824f2194135aaf2194b1913bf9175b8d64df8ffb65930866965b		 ole-package OOXML xl/embeddings/QVSw.tJd5qw Ole10Native stream: OLe10nATIvE 1001895 bytes

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