Malicious PDF — malware analysis report

Static analysis result for SHA-256 81586b388f03249d…

MALICIOUS

PDF

44.9 KB Created: 2021-06-09 07:31:23 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-24
MD5: 71cd04de8a3525c24af671f81363fe6b SHA-1: 0a319e21cebda40832358eca705a27288c0041a0 SHA-256: 81586b388f03249d63777441902e6989b16c68b7ebfbe48f0289c26bdca1bdfd
220 Risk Score

Malware Insights

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

This PDF document contains multiple links designed to lure users into clicking on what appear to be free Robux generators or game hacks. These links redirect to malicious infrastructure, specifically identified as a known malicious redirector. The document body, though heavily obfuscated, contains references to 'free Robux hack' and a URL that aligns with the heuristic findings. The presence of numerous external links suggests a link farm or SEO poisoning tactic to distribute the malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9865

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.
  • 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.
  • 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-hack-pc-2021-game-hack In PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/free-tiktok-followers-no-downloads_GM835599320.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/roblox-codes-for-free-robux-2021_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/prison-life-roblox-hacks_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/free-robux-no-human-verification-no-survey_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/free-robux-hack-no-human-verification_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/can-u-get-free-robux_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/reverse-a-roblox-hack_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/how-to-get-free-robux-com_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/minecraft-fly-hack_GM479516143.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/free-roblox-accounts-with-robux_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/how-to-hack-roblox_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/minecraft-multiplayer-free_GM479516143.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/medkit-free-robux-get_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/how-do-you-get-free-robux-2021_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/roblox-background-2021-its-free_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/roblox-builders-club-free-2021_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/promo-codes-for-free-robux_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/robux-free-gift-card-org-hack_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/free-robux-no-human-verification-or-survey-2021_GM431946152.pdfIn PDF document text
    • http://perpustakaan.fe.unismabekasi.ac.id/katalog-buku/repository/free-robux-no-human-verification-or-survey_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_004_off00005089.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5089 25404 bytes
SHA-256: 17177dde0f770c40631c3c4b55f2cb46f535e131283b45ac0f6bded297fcaf4d
font_01_sfnt_off00008afd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8AFD 18968 bytes
SHA-256: b40abbb39c03f54c03e9ef5e286eeb46dc527f15deefc98f1c255e81c649486c