Malicious PDF — malware analysis report

Static analysis result for SHA-256 791a6e1fddd4194f…

MALICIOUS

PDF

77.6 KB Created: 2021-04-03 20:59:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: 62cfa86f3a32acfcd3afd4761e6a44d1 SHA-1: 1e24e14173d1ff10b9d10c821810a3e2017915a8 SHA-256: 791a6e1fddd4194fee3221f6adc8bc8426a28175ccb8ced98f36f5e19177b82f
186 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The file is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it's part of a link farm. The document body, though heavily obfuscated, suggests a lure related to academic materials. The presence of numerous external URLs, many hosted on disposable domains, strongly suggests a phishing or SEO-based malicious distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://nipisod.ru/wix?keyword=campbell+biology+10th+edition+test+bank PDF link annotation
    • https://cdn.sqhk.co/xipitufekaru/TH2jcib/55355993453.pdfIn PDF document text
    • http://itash.space/71025939903lfhk7.pdfIn PDF document text
    • http://daxavepevepa.mypressonline.com/nuclear_power_plant_operation.pdfIn PDF document text
    • http://tamasolesodaj.mypressonline.com/71780957265.pdfIn PDF document text
    • http://hangookoil.ru/appium_android_press_home_buttoniz4a6.pdfIn PDF document text
    • https://cdn.sqhk.co/puxedimuwo/cghTZWy/rodena.pdfIn PDF document text
    • http://tupujetu.sportsontheweb.net/bio_data_sample.pdfIn PDF document text
    • http://normaa-id.com/zilafumivav1lmnx.pdfIn PDF document text
    • https://cdn.sqhk.co/zirigajer/haJbZjh/jidevezavamof.pdfIn PDF document text
    • http://fimewot.xyz/basesekugokigepaozpoy.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/d75aca97-8403-4cd4-b9e6-54166ef67d7b/70443901694.pdfIn PDF document text
    • https://200c4c3d-185b-4246-b99f-f40cd7065c99.filesusr.com/ugd/3ed902_8a288c98edb64e838df2098334517abb.pdf?index=trueIn PDF document text
    • https://d9226533-59f4-4737-ae77-cfa9cdee5378.filesusr.com/ugd/d7c203_bc00af533f324518acfcf67565307465.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/c7158841-7134-4138-9c0a-7dd0c51db2e0/jatodij.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b2af14fe-d036-493a-ab63-aff07365d674/82300379452.pdfIn PDF document text
    • https://4f65703b-d4c0-4c9c-9e30-73c8cc83ec5d.filesusr.com/ugd/54fa57_d5c4a9e8ac7441e1a5553812c4826418.pdf?index=trueIn PDF document text
    • https://f8071fb1-33dc-4bb9-9fe9-292e0ca0d861.filesusr.com/ugd/253000_3ea926d833044df79562504c041f8c33.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/9c433891-0541-4d3c-960a-74f83776a392/what_are_the_buddhist_sutras.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/05f7eb03-6fcc-4fa0-ba99-6184da01a172/river_flows_in_you_guitar_tutorial_without_capo.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_off0000ef5a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF5A 5684 bytes
SHA-256: 0a929391ab3f227469e732581e3c9a7ed1eabe0f9d5da3783737cd03990a3043
font_01_sfnt_off0001028a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1028A 11384 bytes
SHA-256: 14768d51add08c064dfd966850ac62abc460dbbea902bdfac8b99c427ac9386f

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