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

Static analysis result for SHA-256 8dbf5672166ca668…

MALICIOUS

Office (OLE) / .XLSX

1.41 MB
MD5: 8a64a399bf5789187d97088115174413 SHA-1: a1f28ba3892dbc4508912804305a9264d05b1646 SHA-256: 8dbf5672166ca668a505b52c355f0281257f657d7adb71ff3a12d6389cec2f3c
140 Risk Score

Malware Insights

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

The sample is an encrypted Office document that utilizes embedded OLE objects, with a high-confidence detection of an Equation Editor OLE object. This strongly suggests an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882) to deliver a payload. The document's encryption with a default password further indicates a malicious intent to obscure its contents and delivery mechanism. No specific family could be identified, but the attack pattern is consistent with exploit-carrying documents.

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.