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

Static analysis result for SHA-256 4c2958984443e494…

MALICIOUS

Office (OOXML) / .XLSX

727.7 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-12
MD5: 391ff27a4c2e67eeddaea46ed437bd87 SHA-1: 67e63ed3398114a794f27bd2a4d0fc6f52734ecc SHA-256: 4c2958984443e4946f0d62425c16c8a1fdcc3106b46d3b8d7a52a5ef4778162e
100 Risk Score

Malware Insights

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

The sample is an Excel file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header and size discrepancy, strongly suggesting exploitation of a known vulnerability like CVE-2017-11882. This technique is commonly used to download and execute a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/24lRd4Zq.8HKBI 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
e74ef3ffffd42af1878305a7e24f76296896cc9a89eaf8d126183a5322e144cf		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/24lRd4Zq.8HKBI 1056768 bytes
ooxml_oleobject_00_ole10native_00.bin
2165a453e682492813c74e2dfe9fc871a5b5930c8dd656eb1697cfdd1a82602d		 ole-package OOXML xl/embeddings/24lRd4Zq.8HKBI Ole10Native stream: Ole10natIve 1045564 bytes

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