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

Static analysis result for SHA-256 d426f1fae508a516…

MALICIOUS

Office (OLE) / .XLSX

1.13 MB
MD5: 89815ce5c4fb75d69867f360f0d41de1 SHA-1: b5905136d4ea1b3ed313cbf8b381abd0dc7dcdab SHA-256: d426f1fae508a5168dbb51ea63c1159af102de6bdbd49b9cecde6d7b049d1b20
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.001 Malicious Link: Malicious File T1566.001 Phishing: Spearphishing Attachment T1059 Command and Scripting Interpreter

The OOXML document is encrypted with a default password and contains an Equation Editor OLE object. This object is known to be used as a carrier for exploits, specifically targeting vulnerabilities like CVE-2017-11882. The presence of an Ole10Native stream within the Equation Editor object, with an anomalous size, strongly suggests it contains a second-stage payload. The file's structure indicates it's designed to exploit this vulnerability upon opening.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Default-encrypted OOXML embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • Default-encrypted OOXML exploit carrier layout high OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE
    Default-password encrypted OOXML package contains embedded OLE object parts and additional activation/decoy parts. This layout is common in malicious Excel exploit delivery and requires inspecting the decrypted package.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • Office OOXML encrypted with default VelvetSweatshop password medium OFFICE_DEFAULT_PASSWORD_ENCRYPTED_OOXML
    OLE EncryptedPackage decrypts with Excel's built-in VelvetSweatshop password. Office opens this transparently, and malware uses it to hide OOXML exploit parts from scanners that only inspect the outer OLE container.