Malicious PDF — malware analysis report

Static analysis result for SHA-256 ca793e3befedb3ce…

MALICIOUS

PDF

82.4 KB Created: 2021-04-17 10:07:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 086f80ad25d24a9828a1618ddd27e644 SHA-1: 1be49e1342e1c187fab18bbbd1235ec63c33f0f1 SHA-256: ca793e3befedb3ce1dce63e3670877a4e0c528ca89b2a2320fb73b9239594440
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics, including ClamAV and an ML classifier, indicating malicious intent. It contains a large number of external links, with one suspicious URL pointing to 'jacksth.ru'. The presence of numerous links suggests a link farm or redirection strategy, common in phishing or SEO-based malicious campaigns. No scripts were extracted, but the PDF structure itself is indicative of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://jacksth.ru/strik?utm_term=qualitative+research+design+example+pdf
    • https://cdn-cms.f-static.net/uploads/4425217/normal_60411796ea469.pdf
    • https://cdn.sqhk.co/dulinifijal/srtX8hb/jurassic_world_alive_new_dinosaurs_2019.pdf
    • https://cdn-cms.f-static.net/uploads/4415964/normal_5fd7d98f30cec.pdf
    • https://cdn.sqhk.co/kikepedu/bgfrMvr/big_rig_trucks_for_sale.pdf
    • https://static.s123-cdn-static.com/uploads/4387566/normal_6004df47bfa6b.pdf
    • https://cdn-cms.f-static.net/uploads/4448551/normal_60590ee705cf5.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://3a00e800-a8eb-44ae-aafc-ae9aecab8e06.filesusr.com/ugd/1715bf_fb6d5efb6896482d80069cc9eef78927.pdf?index=true
    • https://s3.amazonaws.com/widofafane/cambridge_pet_exam_practice_tests.pdf
    • https://s3.amazonaws.com/fotepopunaj/brooklyn_nine_nine_episodes_guide.pdf
    • https://d934ed86-632c-4751-b35b-4303166f997e.filesusr.com/ugd/be0f55_aea282d3dfca4a409bbb78b99766fa20.pdf?index=true
    • https://s3.amazonaws.com/tujeviwakirawu/chore_list_chart_template.pdf
    • https://s3.amazonaws.com/tevomenil/fogiluforufufexis.pdf
    • https://uploads.strikinglycdn.com/files/bd01061a-9f3d-41cd-b018-7d9c5d603769/ooma_linx_wireless_phone_jack_for_ooma_telo.pdf
    • https://976edc35-935c-46de-9e6e-e225dbc25668.filesusr.com/ugd/0829d8_a4dca62f617d4a488c52d29e5c11d939.pdf?index=true
    • https://s3.amazonaws.com/tupofelasujewas/50013091352.pdf
    • https://03aaa7dd-6608-466c-a68c-f41c59811c05.filesusr.com/ugd/ae15ca_f4677ae24c8943b097f61ddd97cc2b0c.pdf?index=true
    • https://s3.amazonaws.com/tokudapele/95045875932.pdf
    • https://uploads.strikinglycdn.com/files/96694de9-aaea-4079-a904-3e7e00bb27b3/how_to_calm_someone_down_who_is_stressed_over_text.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
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000eddf.bin
2b097f803b6e98c3b6dfe90cbbc835831742e2200b54ba79c504dfcf44887527		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEDDF 5756 bytes
font_01_sfnt_off0001015a.bin
a924168909d9254d674183309869727e4455749d9fd368e37c7582760d429bbf		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1015A 11212 bytes
font_02_sfnt_off000126a3.bin
a95eff378c135b1ab40d10b3cd1da1bafbc07f86005f57898d079c90d712ddbd		 pdf-font-stream PDF embedded font (sfnt) at offset 0x126A3 16204 bytes

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