Malicious PDF — malware analysis report

Static analysis result for SHA-256 9b538d701ce74653…

MALICIOUS

PDF

37.8 KB Created: 2021-07-05 03:56:55 +07:00 Authoring application: wkhtmltopdf 0.12.6 (via Qt 4.8.7) First seen: 2021-09-29
MD5: df65de2e115285dc9f9d0a10c2bd0b8e SHA-1: b7fdc7852a5a852eb6feb2d71288c38818f8198e SHA-256: 9b538d701ce746538224a33ea6601609488ccc6b5e5a1fdd6787584a59260977
142 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF document contains numerous links to external sites, many of which are also PDFs, suggesting a link farm or SEO manipulation tactic. One prominent URL, http://netcdn.tw/app/406889139/coin-master-hack-ios-jailbreak-game-hack, is presented as a game hack lure. The ML classifier also flagged this PDF as malicious with high confidence.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9886

Heuristics 5

  • 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.
  • PDF links to a 'free generator / game hack' redirector high 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.
  • 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
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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/406889139/coin-master-hack-ios-jailbreak-game-hack PDF link annotation
    • http://www.duchem.ae/uploaded_files/userfiles/files/minecraft-free-download-pc_GM479516143.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/minecraft-jar-free_GM479516143.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/how-to-get-free-robux-on-mobile_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/tiktok-free-folowers-4tiktok-site_GM835599320.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/free-ninja-animation-roblox-robuxian_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/free-coin-master-spins-hack_GM406889139.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/free-robux-hack-2021_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/free-russian-sign-roblox-t-shirt_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/minecraft-windows-10-edition-unlock-full-game-free_GM479516143.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/barren-cheats-roblox_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/free-robux-codes-no-verification_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/coin-master-free-spins-facebook_GM406889139.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/how-to-hack-peoples-roblox-accounts_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/caillou-hack-roblox_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/roblox-twisted-murderer-cheat-engine-2021_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/how-to-make-free-roblox-clothes_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/roblox-free-executor_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/body-roblox_GM431946152.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/coin-master-free-spins-link-download_GM406889139.pdfIn PDF document text
    • http://www.duchem.ae/uploaded_files/userfiles/files/free-robux-just-enter-username_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_002_off0000317e.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x317E 23420 bytes
SHA-256: fe81bdaf4e5e30e64e14600c8b9175cdf1ee3a6adf6482514b2e56a2a7c691d4
font_01_sfnt_off00006675.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x6675 2896 bytes
SHA-256: c1a618813a64314343402b2ec738fc11c4c912460a4c7ae3029924d2f9a229cd
font_02_sfnt_off0000705a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x705A 18404 bytes
SHA-256: 6ea43ab7228851601be35897fda2bac5ac1a9504793d1b77a03120ade39d3544