Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4b457cae1771dd5…

MALICIOUS

PDF

75.2 KB Created: 2021-06-09 17:15:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 38331b21fa1f0fcb94a9dcb65b020f84 SHA-1: 03f3287a92555937a7b5c43c18efd3611409b145 SHA-256: a4b457cae1771dd59097b849335e1b35377d03b1d925154fe964541b942a5cd8
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high probability of malicious intent. It contains a large number of external links, many pointing to disposable hosting, suggesting a link farm designed to manipulate search engine results or redirect users to malicious sites. The document's content, though heavily obfuscated, appears to be a lure related to IELTS preparation, likely to attract unsuspecting users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 6

  • 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.
  • 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://synerhu.ru/pbw?utm_term=ielts+gt+letter+sample
    • https://cdn-cms.f-static.net/uploads/4373243/normal_603a726d1ab53.pdf
    • https://wevuretadoza.weebly.com/uploads/1/3/5/3/135320639/gomuvajebesimix-jabava-fonumumodutuw-janisolurogev.pdf
    • https://duzaguzu.weebly.com/uploads/1/3/1/4/131406181/bifobumetoxaku.pdf
    • https://tekipagitew.weebly.com/uploads/1/3/4/8/134871071/6870375.pdf
    • https://sujebufapu.weebly.com/uploads/1/3/1/3/131379792/vurozuxikugok.pdf
    • https://cdn-cms.f-static.net/uploads/4464532/normal_606258063c53c.pdf
    • https://xedatuvigino.weebly.com/uploads/1/3/4/5/134580066/d87649b21.pdf
    • https://fokokawozele.weebly.com/uploads/1/3/4/8/134888355/9409697.pdf
    • https://makezuxakoje.weebly.com/uploads/1/3/0/7/130739015/dce1f7ff7e8c4b3.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://bawamotijeku.pbworks.com/f/automate_data_entry_in_a_web_form_using_excel_macros.pdf
    • http://jizakatum.pbworks.com/w/file/fetch/144614583/guluzarevagatelo.pdf
    • http://pimepovume.pbworks.com/f/what_are_the_two_main_objectives_of_sustainable_development.pdf
    • https://uploads.strikinglycdn.com/files/687907d6-98c4-47cf-b621-bbf459ddd3af/90229070772.pdf
    • http://jujupaw.pbworks.com/f/cambridge_english_for_business_studies_teachers_book_download.pdf
    • http://finebov.pbworks.com/w/file/fetch/144449517/jesetepimigegivowesi.pdf
    • https://uploads.strikinglycdn.com/files/d516acf0-ad9e-46ac-b741-a56d40b7bd60/16_odu_ifa_and_their_meaning.pdf
    • https://uploads.strikinglycdn.com/files/7e46a63a-6da7-4717-a297-93e09556db44/53808267133.pdf
    • https://uploads.strikinglycdn.com/files/29e851fe-fac1-4467-a774-9c1fbf5a4e69/wiboxawumikanunazajuveli.pdf
    • http://wuranosa.pbworks.com/f/how_to_consolidate_data_from_multiple_workbooks_in_excel_using_vba.pdf
    • http://tazijebep.pbworks.com/w/file/fetch/144419616/21294455551.pdf
    • http://kufujibumufa.pbworks.com/w/file/fetch/144412488/que_es_el_lider_autocrtico.pdf
    • http://zezimin.pbworks.com/w/file/fetch/144411648/butterfly_knife_part_template.pdf
    • http://jolunatimavu.pbworks.com/w/file/fetch/144517605/how_to_escape_alexa_escape_room_car.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ea7b.bin
9d8dd3cc0096f3615f501cad6fbe048ebc764a7538fb1bf78542e8124c8babaf		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEA7B 5076 bytes
font_01_sfnt_off0000fba7.bin
725a3a04efb72c8282d9ce55142f9010083286d2464322bd2dfe627aa25ae08f		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFBA7 10540 bytes

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