Malicious PDF — malware analysis report

Static analysis result for SHA-256 905a873680cd646c…

MALICIOUS

PDF

48.8 KB Created: 2021-06-03 09:36:43 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-05
MD5: 6721054a09db67c341d404103e3bece5 SHA-1: 98b110229ee4f05e68daf7c3824f392227ef36c5 SHA-256: 905a873680cd646cb0dcd348016ab873248a34ea98068c4e8fbfbc7df93d6ad5
202 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1566.002 Spearphishing Link T1204.001 User Execution: Malicious Link

The PDF document contains multiple heuristics indicating a malicious intent, including brand impersonation (Facebook) and a lure for free Robux, directing users to a suspicious URL. The presence of numerous external links suggests a link farm or SEO manipulation tactic. The ML classifier also strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9796

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.
  • 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.online/app/431946152/codes-how-to-get-free-robux-game-hack.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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.online/app/431946152/codes-how-to-get-free-robux-game-hack PDF link annotation
    • http://pustakasma.nurulfikri.sch.id/repository/coin-master-free-spins-reddit_GM406889139.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/minecraft-windows-10-free-with-java_GM479516143.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/how-to-get-free-spins-and-coins-on-coin-master_GM406889139.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/get-free-spins-coin-master-link_GM406889139.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/pubg-uc-2021_GM1330123889.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/roblox-avatar-free_GM431946152.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/coin-master-hack-without-verification_GM406889139.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/coin-master-free-spins-and-coins-blogspot_GM406889139.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/coin-master-sound-daily-free-spins-link-today_GM406889139.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/how-to-change-your-roblox-username-for-free-2021_GM431946152.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/install-free-game-coin-master_GM406889139.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/how-to-get-free-robux-without-downloading-anything_GM431946152.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/can-you-get-robux-for-free_GM431946152.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/free-robux-link_GM431946152.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/free-roblox-account-genrator_GM431946152.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/how-do-i-get-minecraft-for-free_GM479516143.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/free-robux-that-actually-works_GM431946152.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/coin-master-free-spin-and-coins-links-2021_GM406889139.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/free-robux-script_GM431946152.pdfIn PDF document text
    • http://pustakasma.nurulfikri.sch.id/repository/www-free-robux-com_GM431946152.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_004_off00005434.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5434 25616 bytes
SHA-256: f2f96e551ba086e576576c346d20038d9664b9d50d3e142dfa75a06bb9c559b2
font_01_sfnt_off00009007.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x9007 3512 bytes
SHA-256: 20bf1697e2adf851d40ebe6783dfd7e3ad0961666681d856d811a603d9a71270
font_02_sfnt_off00009b9a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x9B9A 18456 bytes
SHA-256: e7ed60d24a78ba6057de20e743a58d73d760a91b60c41324c250f3bd6f119d62