Malicious PDF — malware analysis report

Static analysis result for SHA-256 72ddb4753436f7b8…

MALICIOUS

PDF

44.7 KB Created: 2021-06-11 05:15:41 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-25
MD5: 9ff52ed59ee397a873f22977278d4489 SHA-1: 173e58ab49b3c14fee5e9dc033483811f62732cd SHA-256: 72ddb4753436f7b8583c6c0f67712ddadc0c7b4a8f8981512d913fccc7af60eb
222 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 brand-impersonation credential phishing and 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 7

  • 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
  • Brand-impersonation credential phishing lure high SE_BRAND_CREDENTIAL_PHISH
    Document impersonates a well-known consumer brand and uses account-security / verification language ('unusual activity', 'account on hold', 'verify your account') to steer the reader to a credential-harvesting link. Corroborated by: call-to-action link host does not match the impersonated brand: https://netcdn.tw/app/431946152/free-roblox-gift-card-20219-game-hack.
  • 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-roblox-gift-card-20219-game-hack PDF link annotation
    • https://www.cgalgeria-dubai.com/userfiles/files/coin-master-free-food-for-pet_GM406889139.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/free-robux-without-human-verification_GM431946152.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/100-free-spins-coin-master-2021_GM406889139.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/coin-master-link_GM406889139.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/free-robux-codes-2021_GM431946152.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/free-robux-without-human-verification-2021_GM431946152.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/minecraft-account-hacked_GM479516143.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/how-to-get-free-stuff-on-roblox-2021_GM431946152.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/can-you-give-me-robux_GM431946152.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/instant-robux_GM431946152.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/coin-master-hack-pro-gamers-com_GM406889139.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/free-spins-coin-master-2021-today_GM406889139.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/free-spins-for-coin-master_GM406889139.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/how-do-you-get-free-food-in-coin-master_GM406889139.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/how-you-get-free-robux_GM431946152.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/hack-to-protect-village-on-coin-master_GM406889139.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/how-to-get-free-roebucks-on-roblox_GM431946152.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/roblox-free-robux-website_GM431946152.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/free-spins-coins-coin-master_GM406889139.pdfIn PDF document text
    • https://www.cgalgeria-dubai.com/userfiles/files/coin-master-free-spins-hack-iphone_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_off000050c7.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x50C7 24832 bytes
SHA-256: 478661d98d2dcac20b235e1c15072ffe782372ce225e11e8e81202c0c3d697bd
font_01_sfnt_off00008979.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8979 19140 bytes
SHA-256: 3d7ae1689cb8f27b2195d461b28f859fc13ab6d660e709bff51ac155d281051f

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