Malicious PDF — malware analysis report

Static analysis result for SHA-256 3bce03a637f7cb53…

MALICIOUS

PDF

72.8 KB Created: 2021-04-09 08:27:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-14
MD5: c4f92a44def40d095384cb2fad587ca8 SHA-1: 846a7b78be22fa4edeb94435e29eb2eb215d7ab6 SHA-256: 3bce03a637f7cb53ae7771ff55238ffea1c8b479ea9d9f7d0b9e495d35886c70
186 Risk Score

Malware Insights

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

The sample is a PDF document identified as malicious by ClamAV and an ML classifier. It contains a large number of external links, many pointing to disposable hosting, suggesting a link farm or SEO manipulation tactic. One of the embedded URLs, https://jacksth.ru/strik?utm_term=how+much+does+a+public+administrator+earn+in+nigeria, is flagged as unknown reputation, indicating a potential phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://jacksth.ru/strik?utm_term=how+much+does+a+public+administrator+earn+in+nigeria PDF link annotation
    • https://cdn.sqhk.co/giganopof/b5rgfgi/55081200934.pdfIn PDF document text
    • https://cdn.sqhk.co/fefamuve/hhiihjb/gujovuvapezilezejofuwotuw.pdfIn PDF document text
    • https://cdn.sqhk.co/lolajelor/ifhc5gj/tutiziw.pdfIn PDF document text
    • http://vomojagibolib.iblogger.org/bahnwrter_thiel_formale_analyse.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4473926/normal_604dd7d80f0a0.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4489404/normal_6030ff007ebc2.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4423471/normal_5feff95f5436f.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://8c17aa34-c454-4d6c-a218-8929c845e329.filesusr.com/ugd/808cd0_6539ae4d9da141c1b4b68579a79185ac.pdf?index=trueIn PDF document text
    • https://a181bb3e-7445-4f1f-a1cf-b2fe66c13e92.filesusr.com/ugd/91ce54_b1276a86694747699f89af4e7446a687.pdf?index=trueIn PDF document text
    • https://9e2b3e3a-6a02-4d3b-8ba9-5acc01041672.filesusr.com/ugd/66c878_e243e0d4692141368dcb010f947926f1.pdf?index=trueIn PDF document text
    • https://80cb706b-a9cc-40e6-9cd2-ad5688d6c4a8.filesusr.com/ugd/c84a73_01d2a5e0883d42eda31b106eaea8867d.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/b93257c0-7a2a-4425-94d4-e78b2d1531da/examination_questions_and_answers_on_business_plan.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/cc171261-5ff7-4e85-84d2-e801bcaf87be/honda_gx160_pressure_washer_pump_oil.pdfIn PDF document text
    • http://nekipusixewid.epizy.com/bccl_company_full_form.pdfIn PDF document text
    • https://4b3b4da4-1145-40fd-8a04-0ac29766dab0.filesusr.com/ugd/6c6203_29d95f932b914cf08665808f0baa70cb.pdf?index=trueIn PDF document text
    • https://74df6fe0-557b-4e47-8461-f2df536053d0.filesusr.com/ugd/4dcf4e_e52caa563f444850b8a9b15e8281a2dc.pdf?index=trueIn 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000de9d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE9D 5680 bytes
SHA-256: 6fa50060b56bed1ed769b8e91c265da43ab0b723e0e190dd030832459ee2b8b6
font_01_sfnt_off0000f1c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1C8 10580 bytes
SHA-256: b8153df94026966fdcda4bd0ab179bc233b7ac64eca2dd009f8402be33b10f23