Malicious PDF — malware analysis report

Static analysis result for SHA-256 a1673a4cc7957b28…

MALICIOUS

PDF

67.5 KB Created: 2021-03-28 22:23:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 93d840df524a590bad6f6b6ab18369b4 SHA-1: c36c4413240fab99dde07c35be0ec21a526d19e7 SHA-256: a1673a4cc7957b284a165ba546bf5143b2e369340e62644dc2fbb9d81f8d24f5
196 Risk Score

Malware Insights

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

The PDF contains numerous external links, many of which are part of an SEO link farm, and one prominent URL is identified as an SEO redirector for 'free-download phishing'. The ClamAV detection and ML classifier also indicate maliciousness. The document body, though heavily obfuscated, suggests a lure related to 'geometry answers', aligning with a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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 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.
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • 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://dugedepap.ru/wix?keyword=lesson+10.1+practice+c+geometry+answers PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4460678/normal_6037829d712a8.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4496001/normal_605d874e2c597.pdfIn PDF document text
    • http://itfamily.info/island_survival_game_switchbgnbl.pdfIn PDF document text
    • http://grigolia-studio.ru/wasteland_survival_hack_iosjtlo2.pdfIn PDF document text
    • http://nazhivy.net/myers_psychology_for_ap_3rd_editionh79c8.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4454167/normal_5ffc7e642edce.pdfIn PDF document text
    • http://verefdliyvtorogo.xyz/biomedical_instrumentation_ebookygewq.pdfIn PDF document text
    • http://logawedulukudan.mywebcommunity.org/3641944465.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/nemafu/zunuvefetekifejiremon.pdfIn PDF document text
    • https://s3.amazonaws.com/padanivozeb/prentice_hall_mathematics_california_algebra_1_answer_key.pdfIn PDF document text
    • https://5637a596-61ce-4e67-8953-8fd9cb84b940.filesusr.com/ugd/c20ea7_e6c1bb280b9d47a8af0ecf6d27480624.pdf?index=trueIn PDF document text
    • https://95a83a18-022f-4aa5-9dc2-588eac4c5c4a.filesusr.com/ugd/ccb6ab_66183d3507b6422fa76e3bc68403b602.pdf?index=trueIn PDF document text
    • https://2a6c20f5-091f-48b5-a5be-bf749919b1f6.filesusr.com/ugd/3794ad_d1fc5709c5ca49779f8131a154257426.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/3217b354-17b5-4809-8488-416121f48abe/can_physical_therapy_help_with_scoliosis.pdfIn PDF document text
    • https://s3.amazonaws.com/lowebemuwojiso/english_connectors_exercises_with_answers.pdfIn PDF document text
    • https://s3.amazonaws.com/tosego/define_the_concept_of_sociology_of_education.pdfIn PDF document text
    • http://gukutimaguvuzum.onlinewebshop.net/sistema_mexicano_de_alimentos_equivalentes_2019.pdfIn PDF document text
    • https://0c2a7d7b-be9d-4ef2-a94c-09ca905cc17d.filesusr.com/ugd/7d21c0_00639be5b48347a8b747d82060225cd4.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/72c21d24-8d4c-40fe-becf-0b5f05d06a32/92270542587.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/2e74d8d3-49b9-42a4-a5e2-8f64b33c048e/72441707900.pdfIn PDF document text
    • https://e7f45dcf-1957-410e-85b1-216e85a225c4.filesusr.com/ugd/a2c2bc_d888b799d080489a80ab7655c5c88c63.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_off0000c90e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC90E 5584 bytes
SHA-256: c0e3fcc7cbde9ff85f3fcf091307dc8b66e023df9660a58a0e0f5934ca94ed26
font_01_sfnt_off0000dc1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC1A 10824 bytes
SHA-256: 66570ccda1e32b966b465b7223f54f477f6c5e913f1443b1d79895f9511f81f3