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

Static analysis result for SHA-256 37561f0ef0aa53dc…

MALICIOUS

Office (OLE) / .XLSX

1.25 MB
MD5: 992f7d28a5bc4bcab29dc95251c0a875 SHA-1: 783de9fac328cec6b95fd531ef843e504a3f249d SHA-256: 37561f0ef0aa53dcf9b5e1c2a0fcf614e0f68602c8409182faa8735dd9981a0e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object appears to be a carrier for a malicious payload, indicated by an anomaly in the Ole10Native stream. The presence of the Equation Editor OLE object strongly suggests exploitation of a known vulnerability, likely CVE-2017-11882, to execute arbitrary code.

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.