Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4e53d07ca200f4d…

MALICIOUS

PDF

77.9 KB Created: 2021-10-09 23:46:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 925e1175827c377d9af383f3275a12ef SHA-1: 95438cc0ec5a48a5c23c4d5bbbd9a2548148eb42 SHA-256: a4e53d07ca200f4dfd488a6ea3d3e63e5648042db6e62af99dfcf6bef15daedd
156 Risk Score

Malware Insights

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

The PDF contains a large number of links, many pointing to compromised WordPress upload directories, indicating it functions as a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. The file's structure and numerous external URIs are consistent with a malicious PDF designed to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9984

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://krisoc.ru/uplcv?utm_term=holstein+cows+for+sale PDF link annotation
    • https://nicemexico.net/wp-content/plugins/formcraft/file-upload/server/content/files/1613baa3424255---37521759319.pdfIn PDF document text
    • http://harasim.cz/uploaded/files/perisa.pdfIn PDF document text
    • https://e-uchebnici.com/img/file/natogosevaminixaf.pdfIn PDF document text
    • https://sdyh.gr/wp-content/plugins/super-forms/uploads/php/files/r4ihisr64b0uq92p2vbsdf2jr2/nadovepimufomuz.pdfIn PDF document text
    • http://gk-eventus.ru/admin/ckfinder/userfiles/files/65545754515.pdfIn PDF document text
    • http://brilspa.ro/userfiles/file///fajititunufiteges.pdfIn PDF document text
    • https://dom4m.by/userfiles/files/9515417122.pdfIn PDF document text
    • http://sofia-es.tokyo/yamituki-n/uploads/files/95496226211.pdfIn PDF document text
    • http://archpiudue.com/userfiles/files/fagilapal.pdfIn PDF document text
    • http://www.bargiel.com.pl/ckfinder/userfiles/files/75349295699.pdfIn PDF document text
    • https://evpersoneli.net/ev-personeli/file/zisad.pdfIn PDF document text
    • http://smarttechsolutionukltd.com/uploaded_files/userfiles/files/koxadajosutekuwijalam.pdfIn PDF document text
    • http://turar-mussin.com/userfiles/File/nujena.pdfIn PDF document text
    • http://parikshitconstruction.com/uploads/gawofinesetuxesajom.pdfIn PDF document text
    • https://angel-juicer.com/FileData/ckfinder/files/20210926_7ACDA81E1EEBC2FE.pdfIn PDF document text
    • http://dptour.net/bot/ckfinder/uf/files/64584649637.pdfIn PDF document text
    • https://chandrakantmusicacademy.org/ckfinder/userfiles/files/63936870753.pdfIn PDF document text
    • http://www.champcaregivers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ba58e21d88---94758425817.pdfIn PDF document text
    • https://mkserwis.pl/userfiles/file/80263327677.pdfIn PDF document text
    • https://samsungklima.net/upload/ckfinder/files/xoxuf.pdfIn PDF document text
    • https://www.aledrukujemy.pl/ckfinder/userfiles/files/vojavixatojulajid.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c997.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC997 18700 bytes
SHA-256: 1f2b1b2223fec5adf231f32be7134e9c0a718f8f27845cf43b6f1ce8f95093a4
font_01_sfnt_off0000fa46.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA46 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001125d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1125D 10404 bytes
SHA-256: f2812aca4e798b5c5d8298797800e425055e256d88a290bae9de655fb4b30955