Malicious PDF — malware analysis report

Static analysis result for SHA-256 1d37d837b2972fe2…

MALICIOUS

PDF

36.0 KB Created: 2021-05-12 09:08:00 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-08-25
MD5: db4d648f562d75e87b5e772078b70642 SHA-1: af5d306255161472975e73cc66045388fde32751 SHA-256: 1d37d837b2972fe264bdd380b31e4f02345ded001935fe7c3166013a4aa7540c
170 Risk Score

Malware Insights

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

The PDF document contains a lure for a "free Robux generator" and displays a fake CAPTCHA, prompting the user to click a link. This link, 'https://netcdn.xyz/app/431946152/free-robux-2021-no-verification-game-hack', is associated with malicious redirector infrastructure. The overall pattern suggests an attempt to trick the user into downloading a malicious payload, likely through a social engineering pretext.

Machine Learning

  • Nyx PDF Classifier clean score 0.0243

Heuristics 5

  • PDF links to a 'free generator / game hack' redirector critical PDF_GAME_HACK_REDIRECT_LURE
    PDF's clickable action targets a redirector of the form /app/<id>/<slug>-game-hack — the landing-page shape of a large SEO 'free spins / generator / game hack' lure family that funnels victims through rotating disposable hosts to a malware/scam payload. The multi-link variants also trip ML/link-farm rules; this catches the single-link variants that otherwise score clean. CRITICAL on its own: the /app/<id>/<slug>-game-hack path shape is unambiguous scam infra, and the host rotates so a host-list match can't be relied on.
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Fake CAPTCHA / human verification prompt high SE_FAKE_CAPTCHA
    Document displays a fake CAPTCHA or human-verification prompt — used to trick users into running commands or pressing keyboard shortcuts
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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 https://netcdn.xyz/app/431946152/free-robux-2021-no-verification-game-hack In PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_003_off0000321b.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x321B 24108 bytes
SHA-256: f3676809f16c25e20992e5855ab21064fe5a251b5d4375c0c1bdecc6d28c7abe
font_01_sfnt_off0000692a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x692A 19004 bytes
SHA-256: 66494d2150ad1cf2ec2ec7771a558690eaf6f54b49f1e3390ebbe78937767b49