Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef4991b356ae0fb8…

MALICIOUS

PDF

81.3 KB Created: 2021-05-16 12:11:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-25
MD5: 631da38ec108d4cf8657550dfe3540ac SHA-1: 445a57a9c8f414f578db589e25d503a588a94846 SHA-256: ef4991b356ae0fb89afb00eb91082f2df9cc44a6c439c7992e5d365235aa19e1
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file contains numerous embedded links, many of which point to disposable hosting or known malicious redirector infrastructure. The document body, though heavily obfuscated, appears to be a lure related to creating PDF files on mobile devices, likely intended to drive traffic to malicious sites for phishing or malware distribution. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 5

  • 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 links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://crophysi.ru/strik?utm_term=como+hacer+un+archivo+pdf+en+celular+gratis In PDF document text
    • http://idealicacolumbia.site/jusozomesaramitn9m35.pdfIn PDF document text
    • https://cdn.sqhk.co/rekubapapup/XjcLhcW/rafububutuxamijon.pdfIn PDF document text
    • https://cdn.sqhk.co/noxisoture/esLHyib/bijuvolivupevopizemixax.pdfIn PDF document text
    • http://fixmarker.fun/is_there_a_grace_period_for_cdl_medical_card_colorado7uq1r.pdfIn PDF document text
    • http://jokojujut.medianewsonline.com/91196247982.pdfIn PDF document text
    • https://cdn.sqhk.co/vixukose/Daejdgg/absorption_rate_in_real_estate_formula.pdfIn PDF document text
    • http://myluckybet.xyz/742056731616m8kd.pdfIn PDF document text
    • http://lamisorosasam.mywebcommunity.org/mathematics_3000_secondary_4_answers.pdfIn PDF document text
    • https://cdn.sqhk.co/gufezitaxato/ihijPhg/3564500899.pdfIn PDF document text
    • http://thedouche.xyz/lee_precision_modern_reloading_manual_2nd_edition293bt.pdfIn PDF document text
    • https://cdn.sqhk.co/xigofidiw/Ahgxhih/licence_plate_game_checklist.pdfIn PDF document text
    • https://cdn.sqhk.co/kakapoxavu/iehjqan/kiddom_classroom_management.pdfIn PDF document text
    • https://cdn.sqhk.co/tijanukubo/aibgjtD/dudewetivaluludow.pdfIn PDF document text
    • http://soul-felt.com/laxowogerfumj6.pdfIn PDF document text
    • http://bipiraxas.iblogger.org/fda_grain_free_dog_food_report.pdfIn PDF document text
    • https://cdn.sqhk.co/gujowaxexag/xhhigdL/my_mobile_app_login.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://velelakolifuvu.onlinewebshop.net/rixikobinijisavolelejixed.pdfIn PDF document text
    • http://poparefonuvukoj.rf.gd/parts_of_human_skeleton.pdfIn PDF document text
    • https://s3.amazonaws.com/rezugekolaba/nageledifur.pdfIn PDF document text
    • https://s3.amazonaws.com/kovilowab/celiac_disease_histopathology.pdfIn PDF document text
    • http://fopekexu.epizy.com/16707029241.pdfIn PDF document text
    • http://bozagasixafovo.atwebpages.com/cdna_library_construction_steps.pdfIn PDF document text
    • https://s3.amazonaws.com/sisaxu/57120941944.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://scripts.sil.org/OFLIn 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_off0000e58d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE58D 5532 bytes
SHA-256: a9ce4530112ab69fc0741dca7863af3624dda359b1e7628cc2000fb57cbb0419
font_01_sfnt_off0000f83b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF83B 11600 bytes
SHA-256: 015bfa080e7ebfbdfc11d2cfc659baee51537a95aa27a3d4937bd40f7cd30eb0
font_02_sfnt_off00011e3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E3B 17412 bytes
SHA-256: 562189104e3f9a580d762007df45f7e881aa69a4fc086e8adcc09619f7dbc0d8