Malicious PDF — malware analysis report

Static analysis result for SHA-256 2558c949e34194be…

MALICIOUS

PDF

77.5 KB Created: 2021-03-15 01:41:40 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: 8f653e3c6b901cb6570e2eede34a5c57 SHA-1: bb108585d08fb816a5e662676b6ee67979530ee6 SHA-256: 2558c949e34194bee6cf2b63e38cf2ff491618940ebdc89be2bfdd69f58119b0
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample is a PDF document identified as malicious by ClamAV and an ML classifier. It contains a large number of external links, many pointing to other PDF files, indicating a link farm designed to distribute malicious content or phish users. The primary URL observed is `https://jacksth.ru/wix?keyword=dwarf+fortress+forgotten+beast+strategy`, which likely serves as an entry point to this network of links. The document's structure and content suggest it was generated by `wkhtmltopdf`, a tool often used to create PDFs from web content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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.
  • 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://jacksth.ru/wix?keyword=dwarf+fortress+forgotten+beast+strategy PDF link annotation
    • https://cdn.sqhk.co/nufesewepi/mxgcYgm/87343353330.pdfIn PDF document text
    • https://cdn.sqhk.co/juwafajem/fjjxlJp/34061183460.pdfIn PDF document text
    • https://cdn.sqhk.co/bumajanivosi/giifigP/66139457843.pdfIn PDF document text
    • https://cdn.sqhk.co/rapowipijes/hiZQhg6/heart_of_steel_mobile_legends_new_name.pdfIn PDF document text
    • https://cdn.sqhk.co/nixuvaxuw/jgTHihf/pixelmon_mod_for_minecraft_pe_apk.pdfIn PDF document text
    • https://cdn.sqhk.co/lorotukogof/7idiagj/diwizerobatibejaduxut.pdfIn PDF document text
    • https://cdn.sqhk.co/zadexona/e23jtWj/places_to_get_bubble_tea_near_me.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://c9b0c9dc-51ad-46ec-84b2-dbc26df53712.filesusr.com/ugd/b6f588_aa3004cc5fa5462aae766fd9e177cfc1.pdf?index=trueIn PDF document text
    • https://f1cb2ec4-a82d-4768-8a06-5236a2db220e.filesusr.com/ugd/a2e20a_fad94c3d07db4805be3958f0afa881e9.pdf?index=trueIn PDF document text
    • https://4cd5eafb-d261-4666-a528-29b55b1676c1.filesusr.com/ugd/8dde66_9c1ebad9c8c64816bc1542c4e38a8b54.pdf?index=trueIn PDF document text
    • https://6a1e2a5f-c456-4288-b9d5-5378f87870fb.filesusr.com/ugd/076fac_4736ee8fb3ac4ad3be24ae631131d182.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/31e546ae-57a9-4459-8d37-13a96f67acad/66160466478.pdfIn PDF document text
    • https://aed022ca-8a9d-452d-9022-56a74a585a14.filesusr.com/ugd/4d548e_97ba881cd1034717a86d9740e6c88f96.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/87214e8a-d25a-48f8-bf58-7ffe4e1bd6a7/what_does_ka_mean_on_a_cobra_radar_detector.pdfIn PDF document text
    • https://d6ac5066-27fc-4e71-a07d-b30af50dfe8b.filesusr.com/ugd/934fc3_f725793606fa4abcbd34b9ebbcdf7d7a.pdf?index=trueIn PDF document text
    • https://8a6b9437-e7f2-49d7-8c24-351b272aa67a.filesusr.com/ugd/b18e4d_611484ddc9394c399ea8cd78c8a6ded3.pdf?index=trueIn PDF document text
    • https://cd489911-dc6d-4439-b408-84622343fb93.filesusr.com/ugd/d8e941_eca638805f8143e3aa506e12d23fe2d0.pdf?index=trueIn PDF document text
    • https://e0bfa911-60eb-4c53-bd8d-ceec25156dfb.filesusr.com/ugd/0a052f_0b08f177beb3421988ea219dbdbde9c8.pdf?index=trueIn PDF document text
    • https://dc273c12-e125-4738-b2e6-b96bc4bd5eb7.filesusr.com/ugd/c8df25_10a245c8b7934d87b8ab8812d5734bf8.pdf?index=trueIn PDF document text
    • https://ca30e0e0-ecf2-44ab-b6a2-fe26291458be.filesusr.com/ugd/34e21e_01338d5e04344aa38841bf964449ec46.pdf?index=trueIn PDF document text
    • https://8d6920c1-aef5-45ed-b1a0-e693d63948fb.filesusr.com/ugd/0a593f_ca89370bed4b425fa9cdaa29d23d3fc7.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/83ac605d-2e09-4b0c-ac35-7fe706966227/what_to_bring_to_an_interview_teenager_fast_food.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_off0000f337.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF337 5236 bytes
SHA-256: 62f031cf3261a1d8cd80e8769b3802eb2fddbfb16f3c05ed53b459c59b77b11c
font_01_sfnt_off00010537.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10537 10360 bytes
SHA-256: 3b45da348ac1d8bb7c44a645d89a333c8f8a0b848cad126569b2b2213a6adaa6

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