Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4f8826d76431f14…

MALICIOUS

PDF

88.7 KB Created: 2021-07-02 07:06:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 4cbbd6e3ea8e3acf571001b52e27b189 SHA-1: e74d395203c57bf55be43d50362644bc75f760ab SHA-256: c4f8826d76431f1404d5406bac28c9b9acace6bb4852ccec05840dde72fef770
156 Risk Score

Malware Insights

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

The file is identified as malicious by ClamAV and an ML classifier, and exhibits characteristics of a link farm. It contains numerous external URIs pointing to various domains, some of which are associated with compromised CMS uploads or disposable hosting, suggesting an attempt to manipulate search engine results or redirect users to malicious sites. The PDF structure itself does not contain readable content, but the heuristics strongly indicate a malicious intent through its extensive use of external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9952

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://laborke.ru/uplcv?utm_term=factoring+polynomials+calculator+with+solution PDF link annotation
    • http://carolstoecker.com/clients/c/c6/c60e280709801842a26e47e23f21f170/File/79515707088.pdfIn PDF document text
    • http://www.expo-hotel.com/english/wp-content/plugins/formcraft/file-upload/server/content/files/160ddde81a3859---33621499950.pdfIn PDF document text
    • http://afghansolar.com/userfiles/file/74502856883.pdfIn PDF document text
    • http://esoftland.com/userfiles/file/favoxaxonuxaxegelel.pdfIn PDF document text
    • http://bergfin.se/wp-content/plugins/formcraft/file-upload/server/content/files/1607b500dba39f---47887486366.pdfIn PDF document text
    • http://www.gcsystem.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160c011fa9e854---posoxefurevude.pdfIn PDF document text
    • http://yatros.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607bfab287bdd---71596981630.pdfIn PDF document text
    • https://baohohoanglong.com/userfiles/file/28048049843.pdfIn PDF document text
    • https://www.sacproblemleri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a1a3d9736ed---ronajurenem.pdfIn PDF document text
    • https://www.qbuildsoftware.com/wp-content/plugins/super-forms/uploads/php/files/488e1189595515741b9f45d0b866deb2/82236312336.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/v89mpd9lj91m2uhleah7t3u3d7/8307349517.pdfIn PDF document text
    • http://dotacjedlaoze.pl/userfiles/file/jikedelizagidodowofegupog.pdfIn PDF document text
    • http://www.bufolari.com/public/immagini/file/23408687411.pdfIn PDF document text
    • https://storage-in-motion.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b2cd1fedcbc---kapukak.pdfIn PDF document text
    • http://bean2beenefamilytree.com/clients/60578/File/perokab.pdfIn PDF document text
    • https://karinbentum.nl/uploads/file/danugomitupufodipafudezu.pdfIn PDF document text
    • https://abe-rdc.com/userfiles/file/getemexamofefaki.pdfIn PDF document text
    • http://adanateknikservis.web.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160818fa22564b---nilebulovusidolut.pdfIn PDF document text
    • https://eduinfinite.com/wp-content/plugins/super-forms/uploads/php/files/b1c6a97a76545d3ec060c999c588cc39/zofisimomi.pdfIn PDF document text
    • https://eliteswimmingpoolsinc.com/wp-content/plugins/super-forms/uploads/php/files/m74jjuibt0tvmjjc43jvlt6083/furowivofaxelevoluxudexov.pdfIn PDF document text
    • https://bellevuecommunityfoodbank.org/wp-content/plugins/super-forms/uploads/php/files/8a5d8ed3e32ff11f82debc88654ef146/54469676835.pdfIn PDF document text
    • https://coachtourbusrental.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609550b928186---25370470180.pdfIn PDF document text
    • http://kartinatv.org/uploads/files/91935652251.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

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f513.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF513 10964 bytes
SHA-256: 00346d6c16b12a8ec10d9ffe1632197c9488b92a4c3cc31e5c0e184373e61175
font_01_sfnt_off00010e69.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E69 17724 bytes
SHA-256: 852cd16bba7bd5ff10d1ae0ca909fff7ccf7caa12938a4378bfa4fd27372ac11
font_02_sfnt_off00013d1c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13D1C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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