Malicious PDF — malware analysis report

Static analysis result for SHA-256 9df61a6ce3739bf8…

MALICIOUS

PDF

46.7 KB Created: 2021-06-11 13:09:24 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-13
MD5: 8f9e0aaf1f7dc80aba2194e79dcea739 SHA-1: c823ce1993a161065c477ee4a35f6543392c4169 SHA-256: 9df61a6ce3739bf810406a20942b8ab339b9339930dffc6153c5bfcf90e9212e
200 Risk Score

Malware Insights

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

This PDF document employs a fake CAPTCHA lure to deceive users into interacting with malicious links. The primary malicious URL identified is https://netcdn.tw/app/431946152/free-mask-on-roblox-game-hack, which is part of a redirector chain. The document's content and heuristics strongly suggest an attempt to trick users into downloading or executing further malicious content, likely for a scam or to install malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9832

Heuristics 5

  • 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.
  • 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.tw/app/431946152/free-mask-on-roblox-game-hack In PDF document text
    • http://opac.library.uib.ac.id//repository/is-there-any-way-to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://opac.library.uib.ac.id//repository/coin-master-free-spins-reddit_GM406889139.pdfIn PDF document text
    • http://opac.library.uib.ac.id/repository/coin-master-2021-free-spins-link-blogspot_GM406889139.pdfIn PDF document text
    • http://opac.library.uib.ac.id/repository/free-robux-giveaway-no-hacks-2021_GM431946152.pdfIn PDF document text
    • http://opac.library.uib.ac.id/repository/pubg-uc-nedir_GM1330123889.pdfIn PDF document text
    • http://opac.library.uib.ac.id/repository/inappropriate-roblox_GM431946152.pdfIn PDF document text
    • http://opac.library.uib.ac.id//repository/how-to-get-robux_GM431946152.pdfIn PDF document text
    • http://opac.library.uib.ac.id//repository/robuxlove-net-free-robux_GM431946152.pdfIn PDF document text
    • http://opac.library.uib.ac.id/repository/free-things-on-roblox_GM431946152.pdfIn PDF document text
    • http://opac.library.uib.ac.id/repository/best-free-spin-app-for-coin-master_GM406889139.pdfIn PDF document text
    • http://opac.library.uib.ac.id//repository/get-free-robux-now_GM431946152.pdfIn PDF document text
    • http://opac.library.uib.ac.id/repository/how-to-get-free-robux-as-a-kid_GM431946152.pdfIn PDF document text
    • http://opac.library.uib.ac.id//repository/minecraft-114-4-download-free_GM479516143.pdfIn PDF document text
    • http://opac.library.uib.ac.id/repository/50-free-spins-coin-master-links_GM406889139.pdfIn PDF document text
    • http://opac.library.uib.ac.id//repository/get-free-food-in-coin-master_GM406889139.pdfIn PDF document text
    • http://opac.library.uib.ac.id//repository/free-coins-and-spins-in-coin-master_GM406889139.pdfIn PDF document text
    • http://opac.library.uib.ac.id//repository/coin-master-hack-quora_GM406889139.pdfIn PDF document text
    • http://opac.library.uib.ac.id//repository/coin-master-hacks-for-iphone_GM406889139.pdfIn PDF document text
    • http://opac.library.uib.ac.id/repository/how-to-get-free-robux-from-cash-for-apps_GM431946152.pdfIn PDF document text
    • http://opac.library.uib.ac.id/repository/free-shields-coin-master_GM406889139.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_off00004ef9.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4EF9 30632 bytes
SHA-256: 00c8bb2c14fbd78b94672632926ec144398450badb69934c58d4cce5f9ce6f96
font_01_sfnt_off0000936c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x936C 18544 bytes
SHA-256: 4e23dde741cc8e700e1558a1d88ba03c473ebb4d809aeb6cc7237ba0b39b6a8b

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