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

Static analysis result for SHA-256 f1a7c8ee4eb0e122…

MALICIOUS

Office (OLE) / .XLSX

214.1 KB First seen: 2023-03-31
MD5: f308193d31ea452f6b326b395ac1a7fe SHA-1: 25744dbdcc79ee3a6952ecf5eb0e17fbc4e83c4a SHA-256: f1a7c8ee4eb0e1221cfec6ce5be2c0a249cdfba6917b825fde28231ac9ccfdfc
262 Risk Score

Malware Insights

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

MITRE ATT&CK
T1204.002 Malicious File T1071.001 Web Protocols T1566.002 Spearphishing Attachment T1059.001 PowerShell

This Office document is password-encrypted and exploits CVE-2017-0199 via an embedded OLE object. The exploit attempts to download a second-stage payload from the URL http://KKKKKK2K3K3K3K3K3K3K3KK3K3K3KK3K3K3K3KK3K34K4KK5KK5K5K5K5KK5L5K5K5L5KL5K5L5K5LK5L5K5LK5L5K5ERKLERKRELREKLLERKLRLERK4L4K3L4K4L4@198.46.174.176/42.........................42.........................doc. ClamAV identifies this as Xls.Downloader.94c25b356b5a6cac-9978798-0.

Heuristics 7

  • 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.
  • Encrypted Office package with CFB FAT corruption critical OLE_ENCRYPTED_AND_MALFORMED
    Encrypted-package shape co-occurs with FAT-chain corruption — the documented combined evasion form.
  • 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://KKKKKK2K3K3K3K3K3K3K3KK3K3K3KK3K3K3K3KK3K34K4KK5KK5K5K5K5KK5L5K5K5L5KL5K5L5K5LK5L5K5LK5L5K5ERKLERKRELREKLLERKLRLERK4L4K3L4K4L4@198.46.174.176/42.........................42.........................doc