Malicious PDF — malware analysis report

Static analysis result for SHA-256 51828c9fed4a39b9…

MALICIOUS

PDF

125.4 KB Created: 2021-07-20 17:20:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: fad1c0667d936d0a2411545890fc9c7a SHA-1: b3a1141b106b764946fc96a998ccd4cc1dc98f3f SHA-256: 51828c9fed4a39b9ca9f3c79173f6840a111a171ae594e9b39a63992aea0bda9
156 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous URLs pointing to compromised WordPress sites, likely serving as a distribution point for phishing or malware. The use of compromised CMS uploads and disposable hosting for redirecting users is a common tactic in malicious campaigns.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

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://namastehealth.in/wp-content/plugins/super-forms/uploads/php/files/st20rpr8nemgmh88pd5helb9kl/vilusovijitalegezag.pdf In PDF document text
    • https://skvely-kup.cz/files/file/84523069659.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/556vheqi2q67h1hjgs9mm1kpg7/megivumujiz.pdfIn PDF document text
    • https://www.medipratik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608806c201ce7---buwovebe.pdfIn PDF document text
    • https://prsnashville.com/wp-content/plugins/super-forms/uploads/php/files/ce5074be0fe6ab29b49f891f169d7b98/50480119069.pdfIn PDF document text
    • http://www.pianoszimmermann.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16084962292993---64008402431.pdfIn PDF document text
    • http://caopump.com/admin/userfiles/file/32237523600.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/16084785431b5c---60930580891.pdfIn PDF document text
    • https://paloaltospeakerseries.com/wp-content/plugins/super-forms/uploads/php/files/3b408bfe5345ee8938070cf806183542/29659530559.pdfIn PDF document text
    • http://principessavencanice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b7f0faabd43---14825543611.pdfIn PDF document text
    • http://forresterfamilyreunion.com/clients/c/cc/cc72bfd2512333311cc1ef5a4fdef90f/File/63001912505.pdfIn PDF document text
    • http://www.theflightfest.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ca2e90ac214---11638989793.pdfIn PDF document text
    • https://sipare.com.ar/wp-content/plugins/super-forms/uploads/php/files/c75af6or4mn18m5ihi6fklaujv/kivorix.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/16099ba055e3e2---63114915136.pdfIn PDF document text
    • https://termofriz.rs//files/diratepinededesu.pdfIn PDF document text
    • http://nhatnguyen.vn/media/ftp/file/nojobazowawupazadikunun.pdfIn PDF document text
    • http://saovietgroup.com/upload/FCK/file/muxibosefevijimemaxibeg.pdfIn PDF document text
    • https://relleno-acidohialuronico.com/wp-content/plugins/super-forms/uploads/php/files/889389784043c3974e1a140199b6215c/65645025861.pdfIn PDF document text
    • http://gennarimaq.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160781b43f3d73---vuvujukugi.pdfIn PDF document text
    • http://maxitelt.no/wp-content/plugins/formcraft/file-upload/server/content/files/1607d7cc838b7e---gobosokinama.pdfIn PDF document text
    • https://yingzhaoliuart.com/upload/file/15682542257.pdfIn PDF document text
    • http://www.nanodrywash.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608831ca2f1cb---97444570550.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=the+sons+of+godPDF link annotation
    • http://lovewhereyoulv.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/5b96f963ab861ac26fcebb42bf8e02e6/54808162630.pdfIn PDF document text
    • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00016726.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16726 18236 bytes
SHA-256: 8f47f2d961f2b65778fd5405aea8d1429175e181d63ace1c3117b9920b0a56b2
font_01_sfnt_off00018435.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x18435 10096 bytes
SHA-256: 9e0f6fa16771da5a19d09a5c579dca3bb7a8d0a2d2f841b9735ee188374ccc90
font_02_sfnt_off00019a68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x19A68 20028 bytes
SHA-256: d528ec26c23b849ebffeae70c7a483b499ec33f5f519967c5c5c01643d7433a9
font_03_sfnt_off0001ce2c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1CE2C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1