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

Static analysis result for SHA-256 aaa97571b8c81110…

MALICIOUS

Office (OOXML) / .XLSX

657.7 KB Created: 2021-10-11 13:45:42 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2022-11-04
MD5: dc7a60553c10ff9b06e3a1343e081f5b SHA-1: c81603fa9e2f081e1c10ae3de9044888e52df6a2 SHA-256: aaa97571b8c811109ab623de66ca34027193e0e78835abd187f6c5750fc1c6d2
140 Risk Score

Malware Insights

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

The file is an Excel spreadsheet containing an embedded OLE object, specifically identified as an Equation Editor object. High-severity heuristics indicate anomalies within this object, suggesting it carries a malicious payload and potentially exploits a vulnerability like CVE-2017-11882. The presence of a NOP sled further supports exploitation. The document body contains what appears to be a list of cellular store locations and phone numbers, possibly a lure or distraction.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/N9B9Taz.aQ4 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
442ac950e0887ece84646eb1b79287a38cd4d7309b87117d3268c4613939ca16		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/N9B9Taz.aQ4 941056 bytes
ooxml_oleobject_00_ole10native_00.bin
1f620dcbfbf77a79ae4d8322c9b464916d3686afcc595ff75426271cd55ed228		 ole-package OOXML xl/embeddings/N9B9Taz.aQ4 Ole10Native stream: OLe10nAtive 930851 bytes

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