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

Static analysis result for SHA-256 99ed4247dd3a3173…

MALICIOUS

Office (OLE) / .XLSX

855.8 KB
MD5: 03489f904684291b7c9c1b97cb9a1c54 SHA-1: 1ab89df863ed595eaff7efa7b8f915764ac6980f SHA-256: 99ed4247dd3a3173c5aa97ce5a11a62db0dd7eb55b7e4aa5ed5500004a2a9ce7
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 Malicious Link

The sample is a password-encrypted Excel file identified as an exploit carrier. It contains an Equation Editor OLE object, a common technique for delivering exploits. The object exhibits anomalies in its Ole10Native stream, suggesting it carries a malicious payload. The encryption and malformed structure further indicate malicious intent, likely to deliver a second-stage exploit or payload.

Heuristics 6

  • 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.
  • Encrypted Office package with CFB FAT corruption critical OLE_ENCRYPTED_AND_MALFORMED
    Encrypted-package shape co-occurs with FAT-chain corruption — the documented combined evasion form.
  • 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)).
  • 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.