Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0 — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 67fb8eda38e0418c…

MALICIOUS

Office (OOXML) / .XLSX

805.2 KB Created: 2022-05-16 17:34:45 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-08-26
MD5: ee05ad1dc1cb929f940937f816624515 SHA-1: a7bb1cf6ef250607529b9ac5619599f8b6047710 SHA-256: 67fb8eda38e0418cb0dd6acc0114afb6c785dfd1a76bfa3552b4932476b7b841
160 Risk Score

Malware Insights

Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0 · confidence 95%

MITRE ATT&CK
T1204 Malicious File T1559 Component Object Model Hijacking

The file is identified as malicious by ClamAV with the signature Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0. Static analysis revealed an embedded OLE object, specifically an Equation Editor object, which is a common technique for delivering malicious payloads. The anomaly in the Ole10Native stream size suggests it contains a payload, likely a downloader.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/O4.EtDiZ 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
6a432379de98b805e38a807aec215eab18881ff4fbbe5042a7b808c886a29c8d		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/O4.EtDiZ 975360 bytes
ooxml_oleobject_00_ole10native_00.bin
8cbedb1d9211a3200c955ec45ca8f9415a3b7fda3f2f9cf1ba209173e741e816		 ole-package OOXML xl/embeddings/O4.EtDiZ Ole10Native stream: Ole10natiVe 965364 bytes
emf_00.emf
38f17a599ac5d645df3840bbb401710ef81573a747da20abbfc1b7d9a9273b58		 ooxml-emf OOXML EMF part: xl/media/image1.emf 169096 bytes

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