Malicious PDF — malware analysis report

Static analysis result for SHA-256 13917b3c69b86b47…

MALICIOUS

PDF

77.7 KB Created: 2021-09-05 08:45:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-18
MD5: 05efde55b10937d0a91cf6f055b64902 SHA-1: 6f63ae8a67c4e516d7e1ae2c16d6a731d578f601 SHA-256: 13917b3c69b86b4761cacaf04fd5ac2a077cdd3acb5c856710e47f59bcd7447f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It contains numerous links, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to distribute further malicious content. The PDF structure itself is also noted as potentially compromised, with duplicate object bodies.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8458

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://berettyotv.hu/userfiles/files/54059556973.pdf In PDF document text
    • https://propiedades.net/ckfinder/userfiles/files/89091132987.pdfIn PDF document text
    • http://spreewaldatelier.de/img/editor/file/wadaderewelorogigazo.pdfIn PDF document text
    • http://olgapolyakova.com/files/files/xamisexugepagise.pdfIn PDF document text
    • https://thriveelearning.com/wp-content/plugins/super-forms/uploads/php/files/4b0dbed28bceb6b402564ae2e5f2d1c7/5399856664.pdfIn PDF document text
    • https://www.shopveriamici.com/wp-content/plugins/super-forms/uploads/php/files/2ibb6kttbvrjq1q05iloi5a4nn/6046020858.pdfIn PDF document text
    • http://hesexpo.com/img/editor/image/file/22449510438.pdfIn PDF document text
    • http://www.gaviprintpack.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608482f4f1e99---gimusenijasenu.pdfIn PDF document text
    • https://pecsikult.hu/files/file/27334291854.pdfIn PDF document text
    • http://dichvugiayphep.net/hinhanh_fckeditor/file/86962856543.pdfIn PDF document text
    • http://www.acefence.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607132af6ce2f---98730080116.pdfIn PDF document text
    • http://beloezoloto.ru/userfiles/file/4582787238.pdfIn PDF document text
    • http://al-bandak.com/userfiles/file/lozikapusagisisebedonoje.pdfIn PDF document text
    • https://doina.md/fckeditorfiles/file/kapevaxewejigixagelof.pdfIn PDF document text
    • https://espritgt.com/userfiles/file/14955063979.pdfIn PDF document text
    • http://ekolojikweb.net/upld/userfiles/file/jemefabezixadude.pdfIn PDF document text
    • http://amadpich.com/userfiles/file/famogemopuz.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ca04861b9e1---36857311443.pdfIn PDF document text
    • https://hostsolutions.ro/app/webroot/files/userfiles/files/97357532686.pdfIn PDF document text
    • https://bem-sa.com/img/file/jadabitirexatimorarananes.pdfIn PDF document text
    • http://flomojapan.com/upload/files/3159673900.pdfIn PDF document text
    • https://www.icslights.com/wp-content/plugins/super-forms/uploads/php/files/04f84fa1bd05cae2281aebd9fb09bcb6/nefirogapeduki.pdfIn PDF document text
    • http://amtusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d63be39e713---98334004834.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=sistema+respiratorio+para+ni%C3%B1os+de+primaria+pdfPDF link annotation
    • 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_off0000d295.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD295 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000eaac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAAC 10896 bytes
SHA-256: c15db1b821e340a28c6694a000c3e0cec2e21a02426933ea4be7a2c665979df2
font_02_sfnt_off00010391.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10391 17476 bytes
SHA-256: 31aa51e0b0e695df72865956a2a70805bf0c4fe7635eca252912d544ab09d378