Malicious PDF — malware analysis report

Static analysis result for SHA-256 4d6a8bf0762d474b…

MALICIOUS

PDF

33.3 KB Created: 2021-07-19 10:28:59 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-08-25
MD5: 6f25094986bf0af2f263a0bb5f815f35 SHA-1: 216ff37c4f2cc383d06933e1e4dbbf53edbb0f39 SHA-256: 4d6a8bf0762d474bdf633637f839150cfac6ad9a77eb0f48cd42405e1d7cd447
180 Risk Score

Malware Insights

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

The PDF contains a malformed stream and links to known malicious redirector infrastructure, specifically http://netcdn.tw/app/431946152/free-roblox-accounts-with-robux-that-work-2021-game-hack. The document body and embedded URLs suggest a lure for game-related cheats or free items, which is a common tactic for phishing or malware distribution. The ML classifier strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9959

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.
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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 http://netcdn.tw/app/431946152/free-roblox-accounts-with-robux-that-work-2021-game-hack In PDF document text
    • http://akademiatenisa.org/images/free-minecraft-skin-maker_GM479516143.pdfIn PDF document text
    • http://akademiatenisa.org/images/is-minecraft-java-edition-free_GM479516143.pdfIn PDF document text
    • http://akademiatenisa.org/images/free-spins-on-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://akademiatenisa.org/images/rbxfree-com-free-robux_GM431946152.pdfIn PDF document text
    • http://akademiatenisa.org/images/free-robux-promo-codes_GM431946152.pdfIn PDF document text
    • http://akademiatenisa.org/images/how-to-get-free-robux-on-ipad_GM431946152.pdfIn PDF document text
    • http://akademiatenisa.org/images/microsoft-free-robux_GM431946152.pdfIn PDF document text
    • http://akademiatenisa.org/images/coin-master-free-spins-2021_GM406889139.pdfIn PDF document text
    • http://akademiatenisa.org/images/free-printable-minecraft-coloring-pages_GM479516143.pdfIn PDF document text
    • http://akademiatenisa.org/images/minecraft-login-free_GM479516143.pdfIn PDF document text
    • http://en.wikipedia.org/wiki/MIT_LicenseIn PDF document text

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00002bf2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2BF2 21840 bytes
SHA-256: 53e8bdae06a3161c9e4bc4664c4543bef3aa4f917d8e5eb436885e21c2a599de
font_01_sfnt_off00005c30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x5C30 19664 bytes
SHA-256: 8bae07e728b427e96174baf89e971ad8e2c74617409806078ebf0a16f21879c4

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