Malicious PDF — malware analysis report

Static analysis result for SHA-256 81a19429d5a595aa…

MALICIOUS

PDF

34.9 KB Created: 2021-07-04 10:41:50 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-13
MD5: 98082b262e7fd9a732f002d7d55647be SHA-1: 6cda46a3c51e86c322a08b481b0a3d911aad1150 SHA-256: 81a19429d5a595aa19fdb09e9c31e66b0922ce9d25c52817fb641dbd34abaf0a
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains embedded links that redirect to malicious infrastructure, specifically promoting 'free Robux' and game hacks. The presence of a malicious redirector link and the ML classifier's high confidence score indicate a phishing or scam attempt. Although no scripts were extracted, the document's structure and embedded URLs strongly suggest a social engineering tactic to drive traffic to potentially harmful sites.

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/get-free-robux-today-game-hack In PDF document text
    • https://edu.kyst.com.tw/image/data/files/comment-hacker-mad-city-roblox_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/hack-coin-master-xyz_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/roblox-game-download-pc-free_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/free-robux-codes-no-verification-2021_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/roblox-free-noneuy_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/how-to-get-free-robux-inspect-element-no-waiting2021_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/roblox-adopt-me-building-hacks_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/new-free-money-links-coin-master_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/300-free-spins-coin-master_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/free-candy-van-script-roblox-pastebin_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/get-free-spins-coin-master-link_GM406889139.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/how-to-get-free-robux-games_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/www-roblox-cheats-com_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/free-robux-com-real_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/5-free-roblox_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/how-to-make-free-robux_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/how-you-get-free-robux_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/how-to-get-free-hair-in-roblox-2021_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/how-to-get-free-roblox-on-ipad_GM431946152.pdfIn PDF document text
    • https://edu.kyst.com.tw/image/data/files/robuxmatch-com-free-robux_GM431946152.pdfIn PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000306e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x306E 22612 bytes
SHA-256: 58f303b1dce508b4789e2e0d2a7e4d60789a1ee3ce547bda5b218f51e8a17b19
font_01_sfnt_off00006309.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6309 19172 bytes
SHA-256: 3fdd240faf6e1407f7e3e305b0db49c456ea6d47955c0aeac931bfd374d9ce8c

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