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

Static analysis result for SHA-256 e4327e530cd27bd7…

MALICIOUS

Office (OLE) / .XLSX

1.24 MB
MD5: f8e541f0b13fdf630673963461c0504f SHA-1: cf1833e0451721548851000df13c8be29b6ceab4 SHA-256: e4327e530cd27bd7d38f0477aa2337f62de4660823ae001faf85385695f73a27
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an encrypted Excel file that contains an embedded Equation Editor OLE object. This object exhibits anomalies in its Ole10Native stream, suggesting it is being used as an exploit carrier. The presence of multiple high-severity heuristics related to Equation Editor OLE objects and exploit carriers strongly indicates malicious intent, likely to deliver a secondary payload.

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.