Malicious PDF — malware analysis report

Static analysis result for SHA-256 35d25ce65d4ba6d2…

MALICIOUS

PDF

72.8 KB Created: 2021-03-27 10:50:49 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-30
MD5: 6de7b70df695b64640564e27aaa3e413 SHA-1: 53c739a99567ce44d11bb0148715d22782ef8e20 SHA-256: 35d25ce65d4ba6d2ba73493eeb683dc3c9d93427dda25c9f2e6527b1f0decc66
184 Risk Score

Malware Insights

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

The sample is a PDF document identified as malicious by multiple heuristics and a machine learning classifier. It contains numerous embedded URLs, with at least one pointing to known malicious redirector infrastructure (https://yafferge.ru/123?utm_term=best+aerobic+songs+free). The document body, though heavily obfuscated, contains text related to 'aerobic songs' and 'free', suggesting a lure to disguise the malicious intent. The presence of a link farm on disposable hosting further supports a malicious phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://yafferge.ru/123?utm_term=best+aerobic+songs+free In PDF document text
    • http://puzexijabin.mypressonline.com/kawaropeb.pdfIn PDF document text
    • http://supsun-aero.com/cascable_android_alternativei3itc.pdfIn PDF document text
    • http://tryici.xyz/living_clean_quotesiz8kn.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4409604/normal_5fc898026977e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4489259/normal_6022af5f79e67.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4390637/normal_5fd918a1c38ac.pdfIn PDF document text
    • http://kayikciakademi.com/tu_mundo_2nd_editionch656.pdfIn PDF document text
    • http://de-bewertung-id-q2e5t23.top/zedejiwavi7jjqh.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://penobugixova.atwebpages.com/cost_center_accounting_sap.pdfIn PDF document text
    • https://s3.amazonaws.com/sinadi/canon_raw_image_editor_free.pdfIn PDF document text
    • http://gomugugagaf.onlinewebshop.net/calorie_counter_app_free_iphone.pdfIn PDF document text
    • http://betakudo.atwebpages.com/robotic_arm_types.pdfIn PDF document text
    • https://s3.amazonaws.com/vigevot/gipotipunokunojowemon.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/88163276-ae3e-4bdd-8dd1-e0eb30975028/who_sings_i_dreamed_a_dream_in_les_miserables.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3993939d-14ff-4dea-800d-a49388d35c5c/digital_marketing_public_relations_examples.pdfIn PDF document text
    • https://s3.amazonaws.com/vovuzize/96849900930.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000deca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDECA 5204 bytes
SHA-256: 367214e19e1dfe51964bfc54fcde19750aaf3810f5e4e29b3f88121a5b195c23
font_01_sfnt_off0000f096.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF096 11060 bytes
SHA-256: 305d26fed80d6d7d30ae852e03770ccbcf500d9d822fe1d36b303a589b9bfc9d

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