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

Static analysis result for SHA-256 c2ed5c07e10009d7…

MALICIOUS

Office (OLE) / .XLSX

938.1 KB
MD5: b458c6aa5698f25c12c204a241d83d4f SHA-1: e2f3d81b7fa66758dc169bf1d425347cdef393ba SHA-256: c2ed5c07e10009d7491b6d0705c8757ecc069af1bdfd231fcb626f49ae3da1df
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Phishing: Spearphishing Attachment

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object is known to be used to deliver exploits, and the anomaly detected suggests it carries a payload. The specific exploit targeted is likely CVE-2017-11882, a common vulnerability in Equation Editor.

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.