Malicious PDF — malware analysis report

Static analysis result for SHA-256 c90fdaafe2084ae6…

MALICIOUS

PDF

34.7 KB Created: 2021-07-09 07:43:25 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: 44c9b20ddfc22b0f26275a5f82915bab SHA-1: 1c0fa5c95d98550508fddea4d387b791c8841041 SHA-256: c90fdaafe2084ae6e5eb5e5d78b288dd8a459992c976a8823c67037a3fcb85e1
160 Risk Score

Malware Insights

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

The PDF document contains multiple links to known malicious redirectors and lures users with promises of free game currency or hacks. The primary malicious URL identified is http://netcdn.tw/app/431946152/easy-how-to-get-free-robux-game-hack. While no scripts were explicitly extracted, the PDF structure and embedded links suggest an attempt to exploit vulnerabilities or redirect users to malicious sites, likely for credential harvesting or further payload delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 4

  • 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.
  • 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 http://netcdn.tw/app/431946152/easy-how-to-get-free-robux-game-hack In PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/roblox-game-free-download_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/tower-of-hell-roblox-hack_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/i-want-free-robux_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/coin-master-400-spin-link-hack_GM406889139.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/roblox-cheat_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/coin-master-free-coins-links-2021_GM406889139.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/coin-master-mod-version-free-download-2021_GM406889139.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/roblox-apk-hack_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/coin-master-free-spins-link-june-2021_GM406889139.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/free-robux-without-offers_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/minecraft-windows-10-code-free_GM479516143.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/rbl-gg-free-robux_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/coin-master-free-spins-link-iphone_GM406889139.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/free-robux-net_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/roblox-promo-code-to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/coin-master-free-coins-and-spins-2021_GM406889139.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/free-robux-giveaway-live_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/coin-master-hack-without-human-verification-2021_GM406889139.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/robux-game-com_GM431946152.pdfIn PDF document text
    • https://royalhelmet.com.vn/ckfinder/userfiles/files/how-to-get-free-robux-without-human-verification-2021_GM431946152.pdfIn 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
font_00_sfnt_off000030a8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x30A8 22244 bytes
SHA-256: 8c4ac38acbbf40956edd43c0581806019f4162fa75b3a7a73ee13c1b7835e02f
font_01_sfnt_off00006229.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6229 19164 bytes
SHA-256: e4d500aa9da98b19d28a47e4f9041d07d7faef15145a0cabdc472361f1a11a9e