Malicious PDF — malware analysis report

Static analysis result for SHA-256 87621bcfa15eef5f…

MALICIOUS

PDF

251.5 KB Created: 2021-07-03 22:40:38 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-11-25
MD5: 695f65edfa42f647e1b1b1dff448c42e SHA-1: 8fbee1225351a5be2c777141b0d8ec8408febae2 SHA-256: 87621bcfa15eef5faf31a9e93ff499d3e227cb4e07d52b9054f3e1ccfdfd59bb
278 Risk Score

Malware Insights

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

The PDF contains a critical heuristic firing for a malicious redirector link, specifically pointing to 'http://netcdn.tw/app/1330123889/pubg-uc-50-tl-game-hack'. This link is presented as a lure for free game currency or hacks, impersonating brands and using fake CAPTCHA prompts to trick users. The document also exhibits characteristics of MFA/credential phishing, suggesting an attempt to harvest user information or abuse authentication mechanisms.

Machine Learning

  • Nyx PDF Classifier clean score 0.0115

Heuristics 9

  • 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.
  • Fake CAPTCHA / human verification prompt high SE_FAKE_CAPTCHA
    Document displays a fake CAPTCHA or human-verification prompt — used to trick users into running commands or pressing keyboard shortcuts
  • MFA / one-time-code harvesting lure high SE_MFA_LURE
    Document asks for a one-time code, authenticator approval, or MFA confirmation — consistent with credential phishing kits that steal session tokens or abuse multi-factor authentication
  • 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: http://netcdn.tw/app/1330123889/pubg-uc-50-tl-game-hack.
  • 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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 http://netcdn.tw/app/1330123889/pubg-uc-50-tl-game-hack In PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/how-to-get-free-robux-without-human-verification_GM431946152.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/how-to-hack-roblox-accounts-2021-easy_GM431946152.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/coin-master-apk-hack-2021-ios_GM406889139.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/free-robux-hack-no-human-verification-or-survey_GM431946152.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/hack-tiktok-fans-free_GM835599320.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/free-coins-coin-master-link_GM406889139.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/how-to-get-free-clothes-on-roblox-2021-no-bc_GM431946152.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/best-free-roblox-outfits_GM431946152.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/free-coin-master-coins-and-spins_GM406889139.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/how-to-get-minecraft-java-edition-for-free_GM479516143.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/hack-roblox-pc_GM431946152.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/coin-master-hack-apk-iphone_GM406889139.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/coin-master-online-hack-2021_GM406889139.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/coin-master-free-stuff_GM406889139.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/freegames911com-coinmastertipsandcheats2021freecoinsandspins_GM406889139.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/www-coin-master-hack-com_GM406889139.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/roblox-promo-codes-free-robux_GM431946152.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/minecraft-hack-2021_GM479516143.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/games-that-give-free-robux-2021_GM431946152.pdfIn PDF document text
    • http://www.sourcology.com/uploaded_files/userfiles/files/coin-master-games-download-free_GM406889139.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_024_off000380ee.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x380EE 26028 bytes
SHA-256: fd18571fc56cfe3aee65b9f6c9d9b13287b1488e31ee060b6226d2e9002e5078
font_01_sfnt_off0003be36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x3BE36 18508 bytes
SHA-256: 62d77d903d137413a13b5b805c16e6285a4a5c1ee98c2bd9012e41dd137ba1a2

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