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

Static analysis result for SHA-256 caf4f0b64bd425c3…

MALICIOUS

Office (OLE) / .XLSX

1.12 MB
MD5: ef302d177adde99f0a6f2e8a6bc9eda1 SHA-1: ebc1e702f7334f162571ae83a4810fd870766ee3 SHA-256: caf4f0b64bd425c3e04a28606b54a98b4eed7deb03ca7091ad148fddfbc297a8
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing

The file is an encrypted OOXML document that contains an Equation Editor OLE object. This object appears to carry a payload, indicated by an anomaly in the Ole10Native stream. The presence of the Equation Editor OLE object strongly suggests exploitation of a known vulnerability within it to execute arbitrary code, likely leading to the download and execution of a second-stage payload.

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.