Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4acd1114a56f4a4…

MALICIOUS

PDF

48.3 KB Created: 2021-06-04 03:52:05 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-10-27
MD5: fa50f53d6e6cb990bc5ae79bc39914bf SHA-1: 738dd1774587e49fc451807ab69ee4baed5cc967 SHA-256: c4acd1114a56f4a42064688ab0f64ddc2ebad4ae5c4eebc204d570c48bb9e529
340 Risk Score

Malware Insights

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

The PDF contains multiple links to malicious redirectors and SEO spam sites, masquerading as 'free Robux' or 'game hacks' to lure users. It also includes instructions to disable security software and mentions password-protected archives, indicating a multi-stage attack designed to bypass defenses and potentially deliver a payload. The ML classifier strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9871

Heuristics 8

  • 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.
  • Security software disable instruction high SE_SECURITY_BYPASS
    Document instructs the user to disable antivirus or security software — unusual for ordinary documents and high-risk in an unsolicited file
  • Password-protected archive handoff high SE_PASSWORD_ARCHIVE_LURE
    Document gives password instructions for an archive or attachment — often used to keep payloads encrypted until after gateway scanning
  • 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.online/app/431946152/free-robux-with-no-human-verification-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.online/app/431946152/free-robux-with-no-human-verification-game-hack In PDF document text
    • http://library.yamasi.ac.id/repository/coin-master-free-spins-link-deutsch-ios_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id/repository/coin-master-free-spins-may-11-2021_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id/repository/facebook-coin-master_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id//repository/coin-master-hack-apk-no-fb-login_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id//repository/free-minecraft-skins-java_GM479516143.pdfIn PDF document text
    • http://library.yamasi.ac.id/repository/hack-coin-master-site-rssingcom_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id/repository/free-coin-master-spins-2021-link_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id/repository/how-to-get-free-coins-on-coin-master-2021_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id//repository/free-roblox-passwords_GM431946152.pdfIn PDF document text
    • http://library.yamasi.ac.id/repository/minecraft-pe-hack-client_GM479516143.pdfIn PDF document text
    • http://library.yamasi.ac.id//repository/free-coins-coin-master-hack_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id//repository/free-robux-codes-no-verification_GM431946152.pdfIn PDF document text
    • http://library.yamasi.ac.id//repository/free-spins-coin-master-2021-no-verification_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id/repository/bloxpink-free-robux_GM431946152.pdfIn PDF document text
    • http://library.yamasi.ac.id//repository/free-spins-coin-master-android_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id//repository/how-to-get-free-roblox_GM431946152.pdfIn PDF document text
    • http://library.yamasi.ac.id//repository/flip-master-coins-hack_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id//repository/free-robux-no-human-verification-or-survey-or-download-2021_GM431946152.pdfIn PDF document text
    • http://library.yamasi.ac.id/repository/coin-master-gold-cards-hack-english_GM406889139.pdfIn PDF document text
    • http://library.yamasi.ac.id/repository/free-robux-no-verification-2021_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_off00005427.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x5427 29500 bytes
SHA-256: 1d59dffda3ca1a1564148249002e3041b76d8460e173b44c1e2f93a6cf55b95e
font_01_sfnt_off000097ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x97EA 19224 bytes
SHA-256: fee2af4c7f09d7ea12136e2767a6473cb73ac52634d47b0a6a367e18f3240d40

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