Malicious PDF — malware analysis report

Static analysis result for SHA-256 0b66fad68b64c7f3…

MALICIOUS

PDF

47.5 KB Created: 2021-06-09 13:24:58 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-07
MD5: aca86819bd726ef86b8f00f1bf64deea SHA-1: 4a77352d365c0a9d5bebacdb31c2f6b73ff422b7 SHA-256: 0b66fad68b64c7f35280c578b0d985fe4836f0d0da6c3daeff225470b518163d
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The PDF contains multiple heuristics indicating a malicious redirector and brand impersonation lure, specifically targeting users with promises of free Robux and game hacks. The embedded URL `https://netcdn.tw/app/431946152/free-robux-and-obc-game-hack` is identified as a malicious redirector. The document body, though heavily obfuscated, contains references to 'Free Robux' and 'game hack', aligning with the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9769

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.
  • Brand-impersonation credential phishing lure high SE_BRAND_CREDENTIAL_PHISH
    Document impersonates a well-known consumer brand and uses account-security / verification language ('unusual activity', 'account on hold', 'verify your account') to steer the reader to a credential-harvesting link. Corroborated by: call-to-action link host does not match the impersonated brand: https://netcdn.tw/app/431946152/free-robux-and-obc-game-hack.
  • 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-and-obc-game-hack In PDF document text
    • http://elibraryfk.unjani.ac.id/fkrepository/repository/free-coin-spin-daily-link-net_GM406889139.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/elibrary/repository/coin-master-free-spins-link-download_GM406889139.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/fkrepository/repository/today-free-spin-coin-master_GM406889139.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/fkrepository/repository/free-coin-master-hacks-no-verification_GM406889139.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/elibrary/repository/coin-master-free-spin-27_GM406889139.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/elibrary/repository/how-to-hack-someone-on-roblox_GM431946152.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/fkrepository/repository/free-robux-sights_GM431946152.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/elibrary/repository/how-to-get-robux-from-3-invites-free-nitro_GM431946152.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/fkrepository/repository/free-robux-gift-card-giveaway_GM431946152.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/fkrepository/repository/free-robux-generator-no-human-verification_GM431946152.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/fkrepository/repository/coin-master-spin-link-2021_GM406889139.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/fkrepository/repository/roblox-2021-hack_GM431946152.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/elibrary/repository/how-do-you-get-free-robux-without-doing-anything_GM431946152.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/fkrepository/repository/hack-card-collection-coin-master_GM406889139.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/fkrepository/repository/free-robux-500_GM431946152.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/elibrary/repository/free-robux-without-any-verification_GM431946152.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/elibrary/repository/coin-master-hack-tool_GM406889139.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/elibrary/repository/free-minecraft-realms-to-join_GM479516143.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/elibrary/repository/minecraft-mobile-free_GM479516143.pdfIn PDF document text
    • http://elibraryfk.unjani.ac.id/elibrary/repository/how-to-hack-people-in-roblox_GM431946152.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_off0000510d.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x510D 25324 bytes
SHA-256: 5e1a219173a52ead8eda1b8e93ff29ef914cf86381ff7562086df5cbee118021
font_01_sfnt_off00008ab5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x8AB5 3884 bytes
SHA-256: 40b61f8938bd710dc29dc58ba3fde91c245a6a69596ec569b4d27c769ca417cf
font_02_sfnt_off0000975d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x975D 18188 bytes
SHA-256: ec8884d6c93831016d0849b6b33b3691ffd41597d780f068ddd3174ac3be97b0