Malicious PDF — malware analysis report

Static analysis result for SHA-256 35d9b9e6df7412bd…

MALICIOUS

PDF

74.8 KB Created: 2021-09-07 20:54:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 5cab10a7eb4d0aef70247b3d2c5ba80a SHA-1: f5e175320ab95b5b2f4a999e08cabd348119f176 SHA-256: 35d9b9e6df7412bd4311f2e7878013cf8d52983371f584e0b3e153048659dd34
156 Risk Score

Malware Insights

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

The PDF was flagged by ML and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous URLs pointing to disposable or compromised hosting. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, suggesting the primary function is to host links rather than display information.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 http://el-master.ru/userfiles/file/39285398025.pdf In PDF document text
    • http://www.festivalmarrakech.info/wp-content/plugins/formcraft/file-upload/server/content/files/1607f810343857---falir.pdfIn PDF document text
    • http://cermak-expo.cz/data/files/file/datesawazekelesijibuje.pdfIn PDF document text
    • https://livnica-metalurg.com/images/pages/file/xomopepugopisimaz.pdfIn PDF document text
    • http://stigstudiotecnico.it/userfiles/files/74069273157.pdfIn PDF document text
    • http://bagiez.de/userfiles/file/panoxipobejugidofefumop.pdfIn PDF document text
    • http://andreagarciam.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a629ecaf7d---biwuwu.pdfIn PDF document text
    • https://cvenhancer.com/wp-content/plugins/super-forms/uploads/php/files/29c4d383b8584eecac7308205058c4b1/92108098709.pdfIn PDF document text
    • http://chinasoftcore.com/userfiles/file///zudunoladajuw.pdfIn PDF document text
    • http://www.39koratmachinery.com/file_upload/files/50329852933.pdfIn PDF document text
    • https://scavilecis.it/userfiles/file/kogusofajosixilopo.pdfIn PDF document text
    • http://polipadel.com/userfiles/file/texagati.pdfIn PDF document text
    • http://cukiernia-waltar.pl/qcms/userfiles/file/11543725520.pdfIn PDF document text
    • https://www.hotel-restaurant-plainfaing.fr/ckfinder/userfiles/files/43745410812.pdfIn PDF document text
    • https://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/thckq47ssltpo00t2ut3k14g7s/wijarizelat.pdfIn PDF document text
    • http://surtek.biz/image/files/20150116_030150.pdfIn PDF document text
    • http://www.hussco-steel.com/husscofiles/files/tigisiwusavuxi.pdfIn PDF document text
    • http://didula.ru/img/file/6057853303.pdfIn PDF document text
    • http://adabaskimerkezi.com/upload/file/78109316283.pdfIn PDF document text
    • http://mxagproducts.com/upload/browse/file/kasolubatafon.pdfIn PDF document text
    • https://gastrotest.co/ckfinder/userfiles/files/29181783516.pdfIn PDF document text
    • https://mediabandit.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cc24b612655---59366989931.pdfIn PDF document text
    • http://teranor.com/ckfinder/userfiles/files/dumeliruriveroje.pdfIn PDF document text
    • http://kwik-it.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160999c631cdcd---61347626918.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/160aaa7fa80c1b---javimogofatarefaxem.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=contaminaci%C3%B3n+electromagn%C3%A9tica+libro+pdfPDF 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_off0000bf3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBF3A 16776 bytes
SHA-256: 72ec08285e22b1c4720ecf18d7bd699a49cecfca2c8c7a6d6acfab9454555d6a
font_01_sfnt_off0000e96d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE96D 11260 bytes
SHA-256: 86207ddef904ef99fc15bac41dc6b2877c51f2fed810b466f6a853d559383d8b
font_02_sfnt_off000102cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102CF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1