Xls.Downloader.Trojan-aa0b8f388d8573cd — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 71a0ef3bd50d79be…

MALICIOUS

Office (OOXML) / .XLSX

855.4 KB Created: 2022-05-16 17:34:45 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-07-04
MD5: 47bd19f558a74fc037bcf111c5dd387f SHA-1: b7e2c5f0e8d6a898148f338ac626e924e74f437c SHA-256: 71a0ef3bd50d79be4102f44b986804201125803c2476b37635687990b07b092b
160 Risk Score

Malware Insights

Xls.Downloader.Trojan-aa0b8f388d8573cd · confidence 95%

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

The critical ClamAV detection identifies the file as 'Xls.Downloader.Trojan-aa0b8f388d8573cd'. High-severity heuristics indicate the presence of an Equation Editor OLE object that carries a payload-like Ole10Native stream, a common technique for delivering malware. This suggests the file is designed to exploit vulnerabilities or deliver a secondary payload upon opening.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/da.JuHZfz 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
  • 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
5427cd2470571dace5e5ac1fb70e0f982f560ab152f452d91b90c89e46889896		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/da.JuHZfz 1062912 bytes
ooxml_oleobject_00_ole10native_00.bin
b40395c94d6253834868e9ed2d14ccb9c431a170fea971e43216973d9da02f46		 ole-package OOXML xl/embeddings/da.JuHZfz Ole10Native stream: OlE10NAtIve 1051879 bytes
emf_00.emf
38f17a599ac5d645df3840bbb401710ef81573a747da20abbfc1b7d9a9273b58		 ooxml-emf OOXML EMF part: xl/media/image1.emf 169096 bytes

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