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

Static analysis result for SHA-256 4dc4374ec31a770f…

MALICIOUS

Office (OLE) / .XLSX

1.26 MB
MD5: 7c5d51f707b6fd10c4ffb3aa55a23501 SHA-1: 0324118b42e13f842f762c09a1f1bb1c6cb0da73 SHA-256: 4dc4374ec31a770fab9ba859bc17bfc7b7e7a03d50fcbf7a155b2a02eaf4cda7
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that contains an embedded Equation Editor OLE object. This object is flagged as an exploit carrier and carries a payload-like Ole10Native stream, indicating it is likely used to deliver a secondary exploit or payload. The default encryption suggests a common technique for evading initial detection. The presence of the Equation Editor OLE object points towards exploitation of a known vulnerability, such as CVE-2017-11882.

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.