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

Static analysis result for SHA-256 6b7ed46b4b978bc0…

MALICIOUS

Office (OLE) / .XLSX

1.22 MB
MD5: b2b39c5683c85f14d7f9ab852bef94f1 SHA-1: 31e2b7ecfac4f40712a16629a1dc1e41c7e6c991 SHA-256: 6b7ed46b4b978bc0356fd8e5ae04b63b3b5c0c5116dc6272ca0d95f266c621ce
160 Risk Score

Malware Insights

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

The sample is a password-encrypted Excel file that contains an Equation Editor OLE object. This object exhibits an anomaly where it carries a payload-like Ole10Native stream, which is highly indicative of an exploit carrier. The presence of embedded OLE objects, particularly the Equation Editor, strongly suggests the file is designed to exploit vulnerabilities for client execution, likely delivered via spearphishing.

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.