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

Static analysis result for SHA-256 a863456a36c15037…

MALICIOUS

Office (OLE) / .XLSX

1.25 MB
MD5: dc690811dc75f7e3cd425221125b725b SHA-1: 40f2e315f724ee225aecc20d55f75a2fd42cba95 SHA-256: a863456a36c150379d96f82e82812fb9ae8f33db0d54fb63d98d00b9977f6e58
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Phishing: Spearphishing Attachment

The sample is a password-encrypted Office document containing an embedded Equation Editor OLE object. This object exhibits anomalies suggesting it carries a payload, a common technique for exploiting Equation Editor vulnerabilities. The encryption and the presence of the Equation Editor object strongly indicate an exploit carrier designed to execute arbitrary code upon opening.

Heuristics 5

  • 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 document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007+, AES-128)).
  • 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.