Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5c8d124416fcf31…

MALICIOUS

PDF

43.0 KB Created: 2021-05-12 13:52:08 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-08-25
MD5: dabb231549c9c30ef92d7942f646f5a2 SHA-1: b5b518dc3210d3751eb391b448bd631565a3fae6 SHA-256: a5c8d124416fcf314cb82f4ea8e33f64c102748f81e66479f15572fd4fdad05e
248 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF contains embedded JavaScript and numerous links to external sites, many of which are part of a link farm. The primary lure is for 'free spins' or 'free robux', a common tactic for phishing or malware distribution. The embedded JavaScript and malformed stream suggest an attempt to exploit PDF vulnerabilities or deliver a malicious payload, likely redirecting the user to the malicious URL https://netcdn.xyz/app/406889139/get-free-spins-in-coin-master-game-hack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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.xyz/app/406889139/get-free-spins-in-coin-master-game-hack In PDF document text
    • http://legs11.co.za/images/free-robux-glitch_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/sites-to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/roblox-sexually_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/how-to-make-a-roblox-group-for-free_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/free-robux-generator-no-human-verification-2021_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/free-roblox-accounts-with-robux-2021_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/free-coins-and-spins-for-coin-master_GM406889139.pdfIn PDF document text
    • http://legs11.co.za/images/free-robux-no-human-verification-and-no-survey_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/to-get-free-robux_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/free-spin-and-win-coin-master_GM406889139.pdfIn PDF document text
    • http://legs11.co.za/images/free-robux-2021-no-verification_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/spin-coin-master-free_GM406889139.pdfIn PDF document text
    • http://legs11.co.za/images/can-you-actually-get-free-robux_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/how-to-get-free-spins-on-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://legs11.co.za/images/free-robux-no-human-verification-2021_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/como-hackear-coin-master-iphone_GM406889139.pdfIn PDF document text
    • http://legs11.co.za/images/coin-master-game-download-free_GM406889139.pdfIn PDF document text
    • http://legs11.co.za/images/free-robux-codes-generator-no-verification_GM431946152.pdfIn PDF document text
    • http://legs11.co.za/images/minecraft-story-mode-free_GM479516143.pdfIn PDF document text
    • http://legs11.co.za/images/minecraft-windows-10-hacks_GM479516143.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_003_off00004dab.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x4DAB 25528 bytes
SHA-256: 92703aab6fc8a940e59d9d25259fa5099639dd43c9cb2f88fbb9edee7f6dcd19
font_01_sfnt_off000086f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x86F5 17884 bytes
SHA-256: 156f4ef702737132daa243a2c4fee8c0c13bec142009a1eebf0215f7cb8aef95

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