Xls.Downloader.af2fa5c5d0587870-9978799-0 — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 1207973edff0ef7c…

MALICIOUS

Office (OLE) / .XLSX

1.25 MB
MD5: 15a7b46cfd288e54d8e5c715674492e8 SHA-1: 7f973870bcdb63b04320099b3dedaf83142091fd SHA-256: 1207973edff0ef7c17e55d53a3967ea97b6300ecbf85d7abe98f75a09716c0a8
240 Risk Score

Malware Insights

Xls.Downloader.af2fa5c5d0587870-9978799-0 · confidence 95%

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

The file is a password-encrypted Excel spreadsheet that contains embedded OLE objects, specifically identified as an Equation Editor exploit carrier. This strongly suggests an attempt to exploit a client-side vulnerability for code execution. The ClamAV detection name further supports its classification as a downloader.

Heuristics 6

  • 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.
  • 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.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.
  • 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.