Malicious PDF — malware analysis report

Static analysis result for SHA-256 16a2757c19b2a1c2…

MALICIOUS

PDF

49.7 KB Created: 2021-05-12 05:02:55 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-23
MD5: 3cbba8ca58e3c93aea1b0806b94c5361 SHA-1: 7797b0493b26327fc1ed735c11704e93223f2e28 SHA-256: 16a2757c19b2a1c276a375b08e46fa1de502fe43b38a4176768d54b5908867b3
260 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains multiple links to malicious redirectors and SEO link farms, disguised as "free generator / game hack" lures. It also displays a fake CAPTCHA to trick users into interacting with the document. The presence of embedded URLs and the overall structure suggest an attempt to drive traffic to malicious sites, likely as part of a phishing or scam campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9349

Heuristics 6

  • 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.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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-no-downloading-apps-game-hack In PDF document text
    • http://stroygrad-spb.com/images/make-free-robux_GM431946152.pdfIn PDF document text
    • http://stroygrad-spb.com/images/coin-master-free-chest-link_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/coin-master-unlimited-spin-and-coin-hack_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/coin-master-daily-free-spins-link-2021-today_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/free-roblox-clothes-2021_GM431946152.pdfIn PDF document text
    • http://stroygrad-spb.com/images/get-me-robux-for-free_GM431946152.pdfIn PDF document text
    • http://stroygrad-spb.com/images/robloxheroxyz-free-robux_GM431946152.pdfIn PDF document text
    • http://stroygrad-spb.com/images/free-spins-coin-master-links-blogspot_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/coin-master-hacks-free-spins_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/coin-master-free-spin-download_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/free-coins-and-spins-coin-master_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/coin-master-rewards_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/free-spins-coin-master-october-13-2021_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/get-free-robux_GM431946152.pdfIn PDF document text
    • http://stroygrad-spb.com/images/how-to-make-a-free-minecraft-account_GM479516143.pdfIn PDF document text
    • http://stroygrad-spb.com/images/roblox-tix-generator_GM431946152.pdfIn PDF document text
    • http://stroygrad-spb.com/images/how-to-make-my-own-coin-master-cards-hack_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/coin-master-hack-download-apk_GM406889139.pdfIn PDF document text
    • http://stroygrad-spb.com/images/minecraft-windows-10-mod-menu_GM479516143.pdfIn PDF document text
    • http://stroygrad-spb.com/images/coin-master-free-foxy-food_GM406889139.pdfIn PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_003_off00004a3d.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4A3D 31408 bytes
SHA-256: 7e795516c6df307d6ab4f73a2b7ca8664788a2703a9c0e38d7b1d14992e6517c
font_01_sfnt_off00008fb2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8FB2 5696 bytes
SHA-256: 450e3ee45915afe13702bf1d587eb8b9ad88a8d2113419ac9f2fd116a828e139
font_02_sfnt_off00009cc4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x9CC4 19404 bytes
SHA-256: 49b6dfa9b56ae39db803e39cb2f1ecc2093e69bc279e239e32c5359198169209

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