Malicious PDF — malware analysis report

Static analysis result for SHA-256 211f94d8cdeb01a0…

MALICIOUS

PDF

43.5 KB Created: 2021-06-09 04:10:50 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-29
MD5: 556fb802e56de4581c529ef73319eb99 SHA-1: 5990b747e7c9e0e5c820a484e666522941a61851 SHA-256: 211f94d8cdeb01a09252f291d629440c5ce6a2d0dde3e89e081143505de9947e
182 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by an ML classifier. It uses a fake-CAPTCHA lure. The file embeds a large number of external links characteristic of an SEO link farm, routes users through malicious redirector infrastructure and presents a deceptive download button. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9865

Heuristics 6

  • 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.
  • PDF links to a 'free generator / game hack' redirector high 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.
  • 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
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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.tw/app/431946152/free-scripter-roblox-game-hack PDF link annotation
    • https://lib.bunghatta.ac.id/app/repository/to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/how-to-get-free-spins-on-coin-master-without-verification_GM406889139.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/free-robux-no-verification-required_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/how-to-get-minecraft-pocket-edition-for-free_GM479516143.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/free-spins-from-coin-master_GM406889139.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/free-robux-no-verification-2021-ios_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/roblox-royale-high-diamond-hack_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/free-robux-cards-2021-codes_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/free-robux-no-human-verification-or-survey-2021_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/roblox-free-robux-no-human-verification_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/what-are-points-for-in-roblox_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/free-coins-and-spins-in-coin-master_GM406889139.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/apps-to-get-free-robux_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/coin-master-daily-free-spins-link-2021_GM406889139.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/free-roblox-toys_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/how-do-you-get-free-robux-2021_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/free-minecraft-skins-java_GM479516143.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/how-to-get-free-clothing-on-roblox_GM431946152.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/coin-master-fan-page-free-spins_GM406889139.pdfIn PDF document text
    • https://lib.bunghatta.ac.id/app/repository/roblox-free-models_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_004_off0000505f.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x505F 24088 bytes
SHA-256: 50bd467dc562a1d9c2122278b69dc736e08eac169f67d884edc25a91c142acb2
font_01_sfnt_off0000873c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x873C 18348 bytes
SHA-256: 46dd1cfb602bcfde0a77b49765467006fcf46cfd53b401053e3bbb07a92bcf64

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