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

Static analysis result for SHA-256 e56be44ff82710e8…

MALICIOUS

Office (OLE) / .XLSX

1.13 MB
MD5: 9ca6188ffa6e7610504240a8e653a1af SHA-1: c0cdd372d847acda3f851f9b96f74a48f9f6ba0b SHA-256: e56be44ff82710e8a304f15c2db34bed017876b9fb36efc1b84c7ace02e6b88a
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1566 Phishing T1204.002 Malicious File: User Execution T1059 Command and Scripting Interpreter

The file is an encrypted OOXML document containing an Equation Editor OLE object, which is a known exploit carrier. The OLE object exhibits anomalies suggesting it carries a payload, and ClamAV has identified it as a downloader. This indicates the file is designed to exploit a vulnerability via the Equation Editor to download and execute a secondary payload.

Heuristics 5

  • 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.
  • ClamAV: Xls.Downloader.af2fa5c5d0587870-9978799-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.af2fa5c5d0587870-9978799-0
  • 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.