Malicious PDF — malware analysis report

Static analysis result for SHA-256 16bdce541bc6e95c…

MALICIOUS

PDF

81.0 KB Created: 2021-09-16 01:42:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 96d2574f2460581d66c4e64b23309059 SHA-1: 47a9487e24abf8c0e5276ff3684cb9aaba4d85b3 SHA-256: 16bdce541bc6e95c5df21a82ad064adc6bdfef0be93402ff245cc2539d2c7ef7
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many pointing to compromised CMS upload storage and disposable hosting, indicating a link farm designed to redirect users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution. No scripts were extracted, and the document body was unreadable, so the attack pattern is inferred from the URL structure and heuristic firings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://www.nbc.com.vn/ckfinder/userfiles/files/punem.pdf In PDF document text
    • https://shih-tzu.ro/files/file/nipasonuzerukonudodobob.pdfIn PDF document text
    • http://plymouth-logs.co.uk/ckfinder/userfiles/files/maxusepudejapilunoki.pdfIn PDF document text
    • http://www.recetasyconsejos.com/wp-content/plugins/formcraft/file-upload/server/content/files/161396a91941ca---juparajuvi.pdfIn PDF document text
    • http://tgroupsrl.com/userfiles/files/71499503674.pdfIn PDF document text
    • http://fpole.ru/sadm_files/5065912748.pdfIn PDF document text
    • http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/16133a92fc64a3---84182146317.pdfIn PDF document text
    • https://matao.ro/app/webroot/files/userfiles/files/60377163669.pdfIn PDF document text
    • http://bibliotekaludwin.pl/img/upload/files/11273003489.pdfIn PDF document text
    • http://tscyw.net/userfiles/file/20210912191148_jw8hxp.pdfIn PDF document text
    • http://aotem.com/data/home/qxu1780220113/htdocs/uploadfile/files/tovafinigeme.pdfIn PDF document text
    • https://piti.leaddeehub.com/userfiles/files/73424253633.pdfIn PDF document text
    • http://labuchedeberce.fr/userfiles/file/91021790916.pdfIn PDF document text
    • http://anapharmata.hu/ckfinder/core/connector/php/files/99337102379.pdfIn PDF document text
    • https://dla-pracownika.pl/pliki_user/File/53938510954.pdfIn PDF document text
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613f02792ef94---28368311110.pdfIn PDF document text
    • http://tyextractor.com/d/files/55525297289.pdfIn PDF document text
    • https://mangalargalux.com.br/ckfinder/userfiles/files/rijutaxuxala.pdfIn PDF document text
    • http://chinalabware.ru/d/files/55057400865.pdfIn PDF document text
    • https://markapin.com/calisma2/files/uploads/labud.pdfIn PDF document text
    • https://charlesstreetvideo.com/userfiles/file/30920977116.pdfIn PDF document text
    • https://www.profiemg.cz/upload/ck/files/nipadoneware.pdfIn PDF document text
    • http://optikametuje.cz/userfiles/file/fosagikuxikeseb.pdfIn PDF document text
    • https://firesystem.ro/imagini_ws/7945274885.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=how+to+connect+wps+in+androidPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d2e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD2E0 10536 bytes
SHA-256: 598c706fd6256527bd286e22b4b077685e346124b1faad7b6c694dede1f6e870
font_01_sfnt_off0000eb03.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB03 19608 bytes
SHA-256: d0989767ca6b5da02f3090fdf304b41ea7e9a2f4cdba6871355eaeee9ab85860
font_02_sfnt_off00011e66.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E66 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1