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

Static analysis result for SHA-256 1f21596ea84bcdd5…

MALICIOUS

Office (OLE) / .XLSX

927.0 KB
MD5: a41853d4d26267269717ea1c9af5097d SHA-1: 1e52f615407388e209faed2ffc2424df33d76dbe SHA-256: 1f21596ea84bcdd5e1fd0d0bd59434d9412da7a3dabc4329be590c0a76892684
140 Risk Score

Malware Insights

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

The sample is an OOXML file encrypted with a default password, indicating it's an exploit carrier. It contains an Equation Editor OLE object, which is a known vector for exploiting vulnerabilities. The OLE object carries a payload-like Ole10Native stream, suggesting it's designed to execute arbitrary code upon opening.

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.