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

Static analysis result for SHA-256 32de3153bc2f4268…

MALICIOUS

Office (OOXML) / .XLSX

588.1 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-10-11
MD5: c1a52b431177fbd2eb41145ba828b2e4 SHA-1: a43d7df02bbe9bd73e10c720085b661245314b8c SHA-256: 32de3153bc2f4268e83f2b16212065189e0a6350aac9ee052b6f485f01fe2a47
100 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 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 discrepancy between declared and actual stream size. This strongly suggests the Equation Editor is being used as a vector to exploit a known vulnerability for delivering a secondary malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/JErSBiUfZ.lcaLY 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
7aaa46903412d6354b02d3f0bc8930d4715b1f49093680bbaccd222cdb169c1b		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/JErSBiUfZ.lcaLY 860672 bytes
ooxml_oleobject_00_ole10native_00.bin
ab71b322c4d50a2099e029a2f204f19128116782608329cdf197c9d3587af1ec		 ole-package OOXML xl/embeddings/JErSBiUfZ.lcaLY Ole10Native stream: oLe10nATiVe 851168 bytes

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