Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5d76c7375e76183…

MALICIOUS

PDF

86.3 KB Created: 2021-05-07 01:21:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-25
MD5: 3ea435bd202c4c34d610e91c01bdf2ed SHA-1: 68be0b676f760a5c518cee048d6a98b8f39121a4 SHA-256: a5d76c7375e7618384917d7da06098f7355fe2bb1a241607a43ca049d55fb86b
66 Risk Score

Malware Insights

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

The PDF document contains numerous embedded URLs, with one specifically identified as a link farm on disposable hosting. The ML classifier strongly indicates maliciousness. The document's content, though heavily obfuscated, appears to be a lure, likely for phishing or malware distribution, by masquerading as an educational worksheet answer key. The presence of external URIs suggests an attempt to redirect the user to a malicious site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 4

  • 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://mezovuduw.ru/strik?utm_term=two+step+inequality+word+problems+worksheet+answer+key PDF link annotation
    • https://cdn.sqhk.co/sixaxetexaxe/FiffaFz/elevate_science_florida_course_1_answer_key.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4495841/normal_6068c5aae9330.pdfIn PDF document text
    • https://cdn.sqhk.co/gexopoku/6hg8JHT/warpath_game_android.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4410965/normal_5fc7dd00d3c28.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4450876/normal_604699f849b34.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4468828/normal_5fe251a01f5e0.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/8056c07c-e150-4797-b2f0-e2fe39109be6/how_to_qualify_for_a_disability_pension.pdfIn PDF document text
    • http://tujejutid.rf.gd/kagatu.pdfIn PDF document text
    • http://xilibosukotijob.epizy.com/past_tense_regular_and_irregular_verbs_worksheets.pdfIn PDF document text
    • https://cee4a208-09ac-40e0-983f-4c2cc776acbe.filesusr.com/ugd/5ed537_085a2ec8435144889e8832dc9623fdfb.pdf?index=trueIn PDF document text
    • https://a121017b-3fb3-450c-9156-48dd71a9bf80.filesusr.com/ugd/07625c_6d2adca0c0bd49f6b7a1605aa4c96331.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/redegelesibif/83552842641.pdfIn PDF document text
    • http://galojuxutiwas.epizy.com/42666580523.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/8d907874-4c33-47e9-a34a-3ac9f51db1b5/html_tags_for_text_color.pdfIn PDF document text
    • https://s3.amazonaws.com/jumedemimo/what_are_some_characteristics_of_active_listening.pdfIn PDF document text
    • https://adea4596-07c4-4c45-ba97-107779ed6dc5.filesusr.com/ugd/5bd9e2_658e82090f5f4488a6296884dc5a5249.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/2833031a-5463-43c6-b3d5-736573956432/bernat_knit_chevron_baby_blanket.pdfIn PDF document text
    • http://pekoguwomigurup.epizy.com/rudilepenusisukujatodomon.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_off00010e00.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E00 5672 bytes
SHA-256: 3392df6b1b2889d021fee77568b73ff4aa375cf6384e6e002a7fdf6e4deb1931
font_01_sfnt_off00012129.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12129 12464 bytes
SHA-256: d8f9bc1443dbf3a87e000d07601aee32688628e1e5a81e77c7b17ff83e27ccd0

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