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

Static analysis result for SHA-256 1c7f3e664a42b82f…

MALICIOUS

Office (OOXML) / .XLSX

863.2 KB Created: 2022-05-16 17:34:45 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-08-09
MD5: 51aacbd1fd4151150bb04a4ebd047d67 SHA-1: 0b5ca4261ed5564f4fa273aa78a66b5fd4d994e8 SHA-256: 1c7f3e664a42b82ffe077fa1eb6b20cf3485055ccf0676fd2447be2cd50c46eb
200 Risk Score

Malware Insights

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

The sample is an Excel spreadsheet containing an embedded OLE object, specifically identified as a vulnerable Equation Editor object. This object carries a payload-like stream with an anomalous header, indicating it's designed to exploit the Equation Editor vulnerability (CVE-2017-11882) to download and execute a secondary malicious payload. The presence of a NOP sled further supports the exploitation of a buffer overflow vulnerability.

Heuristics 5

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/bgq1eovi7.wKV contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • ClamAV: Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
272a3e07f94c8714d36941ac0a1997bfb306cb77454987320f6b739919413b5b		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/bgq1eovi7.wKV 1024000 bytes
ooxml_oleobject_00_ole10native_00.bin
bb3cdf11bd1c9537d00b155b6c337c425bf96bad73b5a445c533fbd1a02a4d65		 ole-package OOXML xl/embeddings/bgq1eovi7.wKV Ole10Native stream: olE10nAtIVE 1013493 bytes
emf_00.emf
38f17a599ac5d645df3840bbb401710ef81573a747da20abbfc1b7d9a9273b58		 ooxml-emf OOXML EMF part: xl/media/image1.emf 169096 bytes

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