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

Static analysis result for SHA-256 2e5238cc6123d63a…

MALICIOUS

Office (OLE) / .XLSX

1.28 MB
MD5: dcd562663c30f8f6d5e8fba1d4035863 SHA-1: 9d0405ad7beda12a0cdc538ad2f48b0d4e6369cb SHA-256: 2e5238cc6123d63a4f38027cd3495dcfefd70fcbae4150231f9a07abf3c7d02f
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.002 Malicious File

The sample is an OOXML file encrypted with a default password, indicating it's an exploit carrier. It contains multiple Equation Editor OLE objects, a known vector for exploiting Equation Editor vulnerabilities. The presence of an anomalous Ole10Native stream within the Equation Editor object suggests it's designed to deliver a secondary 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.