Malicious PDF — malware analysis report

Static analysis result for SHA-256 d19a9b8f639541a9…

MALICIOUS

PDF

34.3 KB Created: 2021-07-09 16:29:48 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-11-23
MD5: 96c6f7d4761d991a74d277370316193c SHA-1: 52d1dca3b197798c69fbaf5caa1e2190cbe41016 SHA-256: d19a9b8f639541a987b7658409ce64f7e2929209fbcba96f8dd8313c59890fee
240 Risk Score

Malware Insights

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

The PDF contains numerous links to external sites, many of which are hosted on domains associated with link farms and malicious redirectors. The document body and extracted URLs suggest a lure for game hacks and cheats, likely to deliver a second-stage payload or phish for credentials. The malformed stream length heuristic indicates an attempt to exploit PDF parsing vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9984

Heuristics 6

  • 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.
  • 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.
  • 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/406889139/coin-master-free-spins-ios-app-game-hack In PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/robux-free-gift-card-org-hack_GM431946152.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/how-to-get-free-money-on-rocitizens-roblox_GM431946152.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/how-to-get-cheats-in-roblox-jailbreak_GM431946152.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/coin-master-links-free-spins_GM406889139.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/como-hackear-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/coin-master-hack-tool-for-pc_GM406889139.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/free-coin-and-spin-in-coin-master_GM406889139.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/your-bizzare-adventure-script-esp-free-2021-roblox_GM431946152.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/free-minecraft-website_GM479516143.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/free-coins-and-spins-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/roblox-murder-mystery-2-speed-hack_GM431946152.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/minecraft-for-free-games_GM479516143.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/roblox-heroes-online_GM431946152.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/free-roblox-account-with-robux-on-it_GM431946152.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/free-minecraft-alts_GM479516143.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/hack-coin-master-32-mod-apk_GM406889139.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/coin-spin_GM406889139.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/coin-master-free-snacks-link_GM406889139.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/free-robux-no-human-verification-and-no-survey_GM431946152.pdfIn PDF document text
    • http://kmh.ddnsthailand.com/ckfinder/userfiles/files/free-roblox-scams_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_002_off00002fc7.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x2FC7 23072 bytes
SHA-256: 028076a09c8d2f78b2e60696cfaecc7bbc28727a03693164a7571c551a377728
font_01_sfnt_off00006392.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6392 18176 bytes
SHA-256: dc04036921b1963ee7132b828a33de2130f87ab3daccf07c14a967ac057e6417