Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5cabaad91ac58a2…

MALICIOUS

PDF

49.3 KB Created: 2021-06-11 00:27:59 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-24
MD5: f580eb4fb0752d56f7769e713e4d8204 SHA-1: cdaee5b115d31fe57c0ccd8e62a6b1c9179703e1 SHA-256: b5cabaad91ac58a2361d0dd275f51e3f81317c7ed94739e5b9966acd52041ec2
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a lure for a "free Robux" generator, which is a common social engineering tactic. It embeds a link to a known malicious redirector, https://netcdn.tw/app/431946152/free-robux-august-2021-game-hack, which likely leads to further malicious content or downloads. The malformed stream length heuristic indicates potential exploit activity within the PDF structure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

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 https://netcdn.tw/app/431946152/free-robux-august-2021-game-hack In PDF document text
    • http://lib3tell.stptrisakti.net//repository/spin-coin-master-free_GM406889139.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/free-minecraft-skins-java_GM479516143.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/pokemon-go-free-pokeballs-no-human-verification_GM1094591345.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/coin-master-hack-apk-download-for-android_GM406889139.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/coin-master-computer-hack_GM406889139.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net//repository/coin-master-mod-apk-latest-hack-with-unlimited-free-spins_GM406889139.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net//repository/games-for-robux_GM431946152.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/roblox-hacked-accounts-list_GM431946152.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net//repository/free-spins-coin-master-haktuts_GM406889139.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/roblox-gift-card-online-free_GM431946152.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/robux-hack-v6-5_GM431946152.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/free-level-7-exploit-roblox-2021_GM431946152.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/coin-master-100-spin-slot_GM406889139.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net//repository/coin-master-ios-hack-download_GM406889139.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/coin-master-game_GM406889139.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/free-robux-offers_GM431946152.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net//repository/free-roblox-gear_GM431946152.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/download-apk-tiktok-free_GM835599320.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/how-to-use-free-robux-codes_GM431946152.pdfIn PDF document text
    • http://lib3tell.stptrisakti.net/repository/get-free-spins-on-coin-master_GM406889139.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_off00005374.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5374 26148 bytes
SHA-256: ae305de01f782d6639d7f85e54d0582799813c2459ecc90aa8030f7c6934fcfb
font_01_sfnt_off00008f3c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8F3C 5696 bytes
SHA-256: 450e3ee45915afe13702bf1d587eb8b9ad88a8d2113419ac9f2fd116a828e139
font_02_sfnt_off00009c4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x9C4D 18808 bytes
SHA-256: 64c62e90166ae5554982ceffe13073c0a08b00a29631ffb415b1212eb12e1380

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