Xls.Downloader.94c25b356b5a6cac-9978798-0 — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 163bd7245cd7a065…

MALICIOUS

Office (OLE) / .XLSX

64.5 KB First seen: 2022-10-10
MD5: 7fb5b026a99b159b93dab44103c43e25 SHA-1: 2506301c53c8e82c92f129f5098f3e23dcda09da SHA-256: 163bd7245cd7a065332c2fe335c97b9c646e1e2eae4d1b0187df24915301a428
202 Risk Score

Malware Insights

Xls.Downloader.94c25b356b5a6cac-9978798-0 · confidence 95%

MITRE ATT&CK
T1204.002 Malicious File T1071.001 Web Protocols T1059.001 PowerShell T1059.003 Windows Command Shell

The file is a password-encrypted Office document identified as a downloader by ClamAV. It exploits CVE-2017-0199 via an embedded OLE object to fetch a secondary payload from the URL http://document_docs@104.168.32.131/uAAuUASDbjasduhuasduyuASHUDHUSADHUASDU/8....................................................0.doc. The encrypted nature and the exploit carrier suggest a deliberate attempt to conceal malicious activity.

Heuristics 6

  • OLE2Link / URL Moniker → remote loader — CVE-2017-0199 critical CVE likely CVE_2017_0199
    Document contains an embedded OLE link object whose URL Moniker points to a remote URL. When the host file is opened, Office follows the link, downloads the URL, and processes the response based on its Content-Type (HTA -> mshta.exe, RTF → Word, etc.) — the documented CVE-2017-0199 primitive. The URL extension is not a reliable filter; servers can return different payloads to Office's user agent.
  • ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.94c25b356b5a6cac-9978798-0
  • 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.
  • Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007, AES)).
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://document_docs@104.168.32.131/uAAuUASDbjasduhuasduyuASHUDHUSADHUASDU/8....................................................0.doc