Malicious PDF — malware analysis report

Static analysis result for SHA-256 f99b55c95dab91d1…

MALICIOUS

PDF

89.2 KB Created: 2021-04-21 10:47:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 94adcef3b4f37cbec43b6570008c0c6c SHA-1: a92a466e9cbdfa2aaf6d2d3fcc30781cf5b3d886 SHA-256: f99b55c95dab91d1eb311e9744151b018fedb4fcbc329a329c70fb48a89f6e08
126 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which are hosted on disposable domains and appear to be part of a link farm designed to redirect users. The primary malicious URL, https://jacksth.ru/strik?utm_term=usmle+step+1+india, is presented in a context suggesting it's a search result for 'usmle step 1 india', indicating a phishing or scam lure. The ML classifier and ClamAV detection strongly support the malicious nature of this document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9983

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
  • 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://jacksth.ru/strik?utm_term=usmle+step+1+india PDF link annotation
    • http://shopwithsale.website/betika_lite_appev9fk.pdfIn PDF document text
    • http://ygrash.website/gidetoxusirufe8id0g.pdfIn PDF document text
    • http://digitalmicroteter.xyz/emerald_green_bubble_mailersohq52.pdfIn PDF document text
    • http://twenty-promo2020.ru/347351197502imtw.pdfIn PDF document text
    • http://creditscoretracking.info/how_to_solve_a_rubix_cube_step_by_step_2x2n5rs5.pdfIn PDF document text
    • http://profoto22.ru/13299389112y5zux.pdfIn PDF document text
    • http://matroskin.space/gofodemepoxixififemkksv.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://s3.amazonaws.com/vapite/lirofeku.pdfIn PDF document text
    • http://vewevilamavem.rf.gd/lic_jeevan_lakshya.pdfIn PDF document text
    • http://jofawapedoguw.rf.gd/conveyor_roller_guide_rails.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c31b26d3-e954-4c7b-8e20-02f6f1befa29/petty_cash_confirmation_letter_format_in_word.pdfIn PDF document text
    • http://xajizufobuvofo.epizy.com/xenuto.pdfIn PDF document text
    • http://nekufijazenog.epizy.com/chief_examiner_s_report_english_2014.pdfIn PDF document text
    • http://depuniwawugupi.epizy.com/mds_3.0_medicare_discharge_assessment.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/49ac3719-697d-41b2-be2e-93e5fd99320b/9066189858.pdfIn PDF document text
    • https://s3.amazonaws.com/vetamedisoz/fluent_python_clear_concise_and_effective_programming_2nd_edition.pdfIn PDF document text
    • https://s3.amazonaws.com/tubukeganuji/karcher_k4_pressure_washer_not_turning_on.pdfIn PDF document text
    • http://wefuzage.epizy.com/frozen_shoulder_stretching_exercises.pdfIn PDF document text
    • https://s3.amazonaws.com/fifuto/electric_circuits_9th_edition_solution_manual.pdfIn PDF document text
    • https://s3.amazonaws.com/zazelujeju/blues_guitar_chords_progressions.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fe5dfbdf-1515-4a80-996d-98141a54a7a2/64792455996.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/0481823e-1b9c-4512-830b-f6b3d3346223/how_much_does_it_cost_for_a_psychological_evaluation.pdfIn PDF document text
    • http://voronuxo.epizy.com/nudunun.pdfIn PDF document text
    • http://jekalabol.epizy.com/energy_levels_and_atomic_orbitals.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/1e2aa498-f106-4aba-88d4-8fb637615b75/fifty_shades_of_grey_full_movie_in_urdu_language.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
    • https://savannah.gnu.org/projects/freefont/In PDF document text
    • http://www.gnu.org/licenses/In PDF document text
    • http://www.gnu.org/copyleft/gpl.htmlIn PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000103cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103CD 6416 bytes
SHA-256: 15f1f49b80f446e7933a40d6c5645ba9b1ad3ddb6c90b7ed74ec66770e7def8a
font_01_sfnt_off00011396.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11396 4732 bytes
SHA-256: c206a1b08d8b473f322a7d0a2a2f5116c3d788f07170bcd67a613d3a32421e63
font_02_sfnt_off00012389.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12389 10992 bytes
SHA-256: 57c3697f5baa273b972c36402253d7acfbc3f665828723d23c329656646eb151
font_03_sfnt_off00014904.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14904 4324 bytes
SHA-256: cd94ef65598b1866d0653cdd88243d989fd81359c0e770c2d3a4858f1c2f6d34

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