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

Static analysis result for SHA-256 87cdbc6952d3d3f8…

MALICIOUS

Office (OLE) / .XLSX

1.31 MB
MD5: 166e88aa51cd18fb2e6359c9ec67dfce SHA-1: 05619f0bbb2ad20e16bb3f096936e1fc5ce5e14b SHA-256: 87cdbc6952d3d3f8e08344a1a983d4ef8deab4d7725097309202d6b1ebc938ea
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1566 Phishing T1204.002 Malicious File: User Execution of Malicious Code

The sample is an OOXML file encrypted with a default password, indicating it's likely an exploit carrier. The presence of an Equation Editor OLE object with a payload-like Ole10Native stream strongly suggests exploitation of a vulnerability within the Equation Editor. No specific IOCs were extracted, but the attack pattern is clear.

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.