Malicious PDF — malware analysis report

Static analysis result for SHA-256 826ed9e36d12bf6a…

MALICIOUS

PDF

86.2 KB Created: 2021-04-19 11:34:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-25
MD5: 79c1d7b4b2759166a78c6a52491aa25a SHA-1: e737c559a134e35e3b5555ebf8b00ed85c7e3d5f SHA-256: 826ed9e36d12bf6af9bd3aa282f68d6238711defb6e4f5bbdc53829ff3316b1b
126 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many hosted on disposable domains, suggesting it is part of a link farm or SEO spam campaign. The document body, though heavily obfuscated, contains keywords related to "welding for dummies review" and mentions "wkhtmltopdf", indicating an attempt to disguise the nature of the links. The presence of numerous external URIs and the ML classifier's high confidence score strongly suggest malicious intent, likely to direct users to potentially harmful content or phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://fokemale.ru/strik?utm_term=welding+for+dummies+review PDF link annotation
    • https://munerojepoges.weebly.com/uploads/1/3/4/0/134042508/d1264854639a.pdfIn PDF document text
    • https://cdn.sqhk.co/jijasitov/ia6ieHz/87450701544.pdfIn PDF document text
    • https://cdn.sqhk.co/pomisiforuko/ZIth2hg/moist_vanilla_cake_recipe_with_all_purpose_flour.pdfIn PDF document text
    • https://tijogarukaro.weebly.com/uploads/1/3/4/7/134710746/mokixodego.pdfIn PDF document text
    • https://cdn.sqhk.co/naxusepimosa/ieeazSK/41408640383.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
    • http://ridejisedogik.rf.gd/wezexi.pdfIn PDF document text
    • http://xupuwineris.epizy.com/vabokudorakurefezuzoseri.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a5ad92d4-0f3a-4624-8934-d0b9a15b6845/how_many_carbs_are_in_a_soft_taco.pdfIn PDF document text
    • https://s3.amazonaws.com/zabejuvijolu/key_characteristics_and_concepts_of_humanistic_theory.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/45391362-6cf1-45a6-b2f0-7ae513bdd942/how_to_use_wii_remotes_on_dolphin.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/13b13857-8391-432b-8d1f-361137df999a/oreilly_sql_book_free_download.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/40708150-bebf-4d11-90bc-9fa44a482ed8/savigajugidobifibipikax.pdfIn PDF document text
    • https://s3.amazonaws.com/paropabaru/htc_desire_eye_battery_problem.pdfIn PDF document text
    • http://fudejavifexas.epizy.com/flowchart_and_algorithm_in_c_language.pdfIn PDF document text
    • https://s3.amazonaws.com/xisakazelelinim/11125717948.pdfIn PDF document text
    • https://s3.amazonaws.com/sazomo/57692817309.pdfIn PDF document text
    • http://totukaxigobakiw.epizy.com/42002141265.pdfIn PDF document text
    • https://s3.amazonaws.com/rodigapigeta/zobogizite.pdfIn PDF document text
    • http://wadatexutogowig.rf.gd/harga_power_amplifier_crown_xls_2500.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

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000106a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106A1 4984 bytes
SHA-256: b9dbacbb05976ff2223464f7c3dd168f7038e644d5ada03934ab302b2be33e4f
font_01_sfnt_off00011785.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11785 11216 bytes
SHA-256: 9bd6404709e5540597cbe540e60edf9cba8eabb764fafff0f6cc23dae56d1d10
font_02_sfnt_off00013d7d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13D7D 4324 bytes
SHA-256: cd94ef65598b1866d0653cdd88243d989fd81359c0e770c2d3a4858f1c2f6d34

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