Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b31ff3feebeb958…

MALICIOUS

PDF

77.1 KB Created: 2021-03-29 01:45:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 52ce6e77899b396bea468a2b002fa53b SHA-1: 8837c7235e27b6a3ff9d3b7f9e61bb316615796b SHA-256: 5b31ff3feebeb958fe98fb017053672d1905c9a3871c4c65057a20c1b6775549
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, identified as a 'PDF_SEO_LINK_FARM' heuristic, pointing to various PDF documents. One of the primary URLs, 'https://pelibifir.ru/wix?keyword=immune+system+and+disease+worksheet+answer+key', suggests a lure related to educational content. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or distributing further malware via the linked resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://pelibifir.ru/wix?keyword=immune+system+and+disease+worksheet+answer+key
    • http://manamuposa.getenjoyment.net/garmin_vivosmart_3_manual.pdf
    • http://fipizilemuwob.medianewsonline.com/kifililulixogefef.pdf
    • http://pemotutafid.mywebcommunity.org/define_theoretical_framework_in_business.pdf
    • http://vofigasu.medianewsonline.com/counting_worksheets_for_kindergarten.pdf
    • https://mazabutefudoxuw.weebly.com/uploads/1/3/4/0/134017854/0123663f3ab657.pdf
    • https://tasiwusod.weebly.com/uploads/1/3/5/3/135351817/7428031.pdf
    • https://gadolelexuzited.weebly.com/uploads/1/3/4/4/134486477/duxevemosa-retadudebor-sumogumi-tuziv.pdf
    • https://xobiduri.weebly.com/uploads/1/3/1/4/131437628/gejajupufebu.pdf
    • https://rorekejufekate.weebly.com/uploads/1/3/0/7/130740186/pivavabadikole.pdf
    • https://disadoxamegipu.weebly.com/uploads/1/3/4/5/134527150/nerokepeguwuwa-semujafije-kuxavox-rulajado.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://76df98a8-3e94-4eee-a6f5-23e1de06049b.filesusr.com/ugd/54c74c_afdadd45ab6b480fb04c31e2432b20cf.pdf?index=true
    • https://uploads.strikinglycdn.com/files/c099be17-2a66-4bb3-b8ad-2ae5c6c6e394/82560624150.pdf
    • https://uploads.strikinglycdn.com/files/48698f33-f45c-498d-ba68-2ae69b0afae7/jepozukomarazutibir.pdf
    • http://vekejuf.atwebpages.com/84727414910.pdf
    • https://uploads.strikinglycdn.com/files/6dfb563b-4dc4-4936-b573-1d66335c76fa/creative_illustration_andrew_loomis.pdf
    • https://8b2103c5-345b-48fd-98e3-f19c90c4efd0.filesusr.com/ugd/0e2875_a69f100f7091445e8e8d117aec7f5d01.pdf?index=true
    • https://uploads.strikinglycdn.com/files/35d40348-f9ad-4e2c-89ff-e0088ba84cdf/conditional_sentences_exercises.pdf
    • https://uploads.strikinglycdn.com/files/c9ac376e-245d-4045-9bc7-93b7705f5af8/samsung_hw-f550_subwoofer_not_working.pdf
    • https://uploads.strikinglycdn.com/files/144db799-1eaf-43b9-9377-ac39fa88d8a0/37471897179.pdf
    • https://uploads.strikinglycdn.com/files/e0b04029-4b32-4b42-b8eb-e611ff7036ed/statistical_physics_lecture_notes.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_off0000f10f.bin
e6efab981a7396e46c36def62e8789344cb9867ecc785c4fd21a233d5f91df5c		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF10F 5228 bytes
font_01_sfnt_off000102c0.bin
13b330a836a2f6d30863af45f76a066ced270bd0ca1e48d309257e8aed88e5a3		 pdf-font-stream PDF embedded font (sfnt) at offset 0x102C0 10560 bytes

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