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

Static analysis result for SHA-256 d361c015f8263ae4…

MALICIOUS

Office (OLE) / .XLSX

1.16 MB
MD5: 52c370c61ca1c2d65dd36286e45d7cf5 SHA-1: 7b5903fef0781a18621cb454079b6ab1ca9693ec SHA-256: d361c015f8263ae4072a34f2d74a98972edefb4e569919b1f4cd26e044d7ef6f
140 Risk Score

Malware Insights

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

The sample is an encrypted XLSX file that contains an Equation Editor OLE object. This object is known to be used as an exploit carrier, specifically for vulnerabilities like CVE-2017-11882. The 'OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY' heuristic indicates that the Equation Editor object contains a payload-like stream, suggesting it's designed to execute malicious code upon opening. The default password encryption further supports its nature as a malicious carrier.

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.