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

Static analysis result for SHA-256 a0b15387b7db7483…

MALICIOUS

Office (OOXML) / .XLSX

597.9 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2024-07-30
MD5: 45c8ef3abdc3909b8b3c44bc0c6db6a9 SHA-1: cbda964fdb552634e9695e4291af0a9105ac57a5 SHA-256: a0b15387b7db7483b4f37935815c5f3dcaecdb38bf5d0c4aa9b8aae33852f3db
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The XLSX file contains an embedded OLE object, specifically identified as a Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous size, suggesting it is being used to exploit a vulnerability. The presence of a NOP sled further supports the exploitation of a buffer overflow vulnerability.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/rw.lv contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • NOP sled detected high SC_NOP_SLED
    Found 20+ consecutive 0x90 bytes
  • 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
9d7bbdfb8381025c257212aac660e278af652c2342303e4b563e98339715a9cf		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/rw.lv 839680 bytes
ooxml_oleobject_00_ole10native_00.bin
989fbdbe22331373dde98e7d849f9c01359609a1eb9f8189878537c30c6f6e26		 ole-package OOXML xl/embeddings/rw.lv Ole10Native stream: OLE10natiVe 830829 bytes

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