Malicious PDF — malware analysis report

Static analysis result for SHA-256 18ff8c4bad0d02dc…

MALICIOUS

PDF

41.8 KB Created: 2021-05-15 01:44:07 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2026-06-04
MD5: 931b6a6e36a00cb0a2bace975f0a9779 SHA-1: 099748727958b39dcb1850b445593d1a1308ee8f SHA-256: 18ff8c4bad0d02dca7115a984c3aeeb813db0704f34d95218fd643487f35fa85
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document contains multiple links to known malicious redirectors, including one that masquerades as a 'free generator / game hack' for Coin Master. The document body and embedded URLs suggest a social engineering lure to trick users into visiting these malicious sites. While no scripts were explicitly extracted, the PDF format itself can embed JavaScript, and the heuristic firings indicate malicious redirection is the primary intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

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 https://netcdn.xyz/app/406889139/get-free-spins-in-coin-master-game-hack In PDF document text
    • https://knj.com.tw/image/data/files/coin-master-claim-spins_GM406889139.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/coin-master-2021-free-spins_GM406889139.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/free-roblox-exploits_GM431946152.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/how-to-get-free-items-on-roblox_GM431946152.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/coin-master-free-soins_GM406889139.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/free-robux-not-fake_GM431946152.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/cheat-codes-for-coin-master_GM406889139.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/free-roblox-girl-clothes_GM431946152.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/roblox-bux-free_GM431946152.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/what-games-on-roblox-give-you-free-robux_GM431946152.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/coin-master-free-spins-facebook_GM406889139.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/inappropriate-roblox-games_GM431946152.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/roblox-free-robux_GM431946152.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/minecraft-client_GM479516143.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/free-coins-coin-master-2021_GM406889139.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/www-rubux_GM431946152.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/free-spin-coin-master-2021_GM406889139.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/robux-robux_GM431946152.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/minecraft-reach-hack_GM479516143.pdfIn PDF document text
    • https://knj.com.tw/image/data/files/hacks-para-roblox_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
stream_003_off000048df.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x48DF 24972 bytes
SHA-256: 1073e235a8130f8d47a6bf6b6fc448703795ff80f0ed00d3306bb9a14ff9a02e
font_01_sfnt_off00008228.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8228 17884 bytes
SHA-256: 156f4ef702737132daa243a2c4fee8c0c13bec142009a1eebf0215f7cb8aef95

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