Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb71c2e7f3185237…

MALICIOUS

PDF

80.5 KB Created: 2021-03-28 17:39:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: 6410f52d5bc7a14c889435f86ca9f011 SHA-1: 7ba85941089150065d7ae7d8c900918bab5e50d0 SHA-256: cb71c2e7f318523793be98ffb5574ef43c2076c8f51af43c0cd2ea763fd3cfee
186 Risk Score

Malware Insights

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

The file is identified as malicious by ClamAV and an ML classifier, and contains numerous external links, indicating a link farm or phishing attempt. The heuristic 'PDF_SEO_LINK_FARM' suggests the PDF is designed to host many external links, likely for SEO manipulation or to redirect users to malicious sites. The presence of embedded URLs further supports this, although no specific script was extracted to detail its execution flow.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://golowaki.ru/wix?keyword=earthquakes+and+seismic+waves+lesson+quiz+answer+key PDF link annotation
    • http://community-day.ru/40729016086tpnqq.pdfIn PDF document text
    • http://gituwema.iblogger.org/61787034804.pdfIn PDF document text
    • http://pimazisiperej.iblogger.org/archimate_3._0_tutorial.pdfIn PDF document text
    • http://dragonflysagewellness.com/49147118972o9fg6.pdfIn PDF document text
    • http://zinuvudoliku.iblogger.org/46918592352.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://9ebe8999-295a-4f11-87dc-c96f3e1b46ff.filesusr.com/ugd/8de238_8e44ac872c81491c80e7c2341442b8b4.pdf?index=trueIn PDF document text
    • https://2863666b-9d79-467d-9aad-9eeb6dafbdf2.filesusr.com/ugd/6ee3eb_9b8f6c6a3ace46999ffeb79a8191324d.pdf?index=trueIn PDF document text
    • http://fopadunopim.epizy.com/curso_de_ingles_para_nios_gratis.pdfIn PDF document text
    • http://duguteterexu.epizy.com/83059387830.pdfIn PDF document text
    • https://s3.amazonaws.com/kexamoxusinixu/71741480821.pdfIn PDF document text
    • https://be5a03d2-cb36-429a-bb4d-4773f067dd3b.filesusr.com/ugd/b46ca8_1e46950e8f0144519a886dbd9e1b19ba.pdf?index=trueIn PDF document text
    • https://a3c35cc3-4a3f-4d41-ab51-8b3e4b114d30.filesusr.com/ugd/2b25b5_63e0848033f84c9ea854a633f709bd81.pdf?index=trueIn PDF document text
    • http://turagax.rf.gd/49256144584.pdfIn PDF document text
    • https://s3.amazonaws.com/tojazudibumogab/net_2018_answer_key_english.pdfIn PDF document text
    • https://3568ea06-17fa-4787-91ae-86b9aa918cbd.filesusr.com/ugd/8ade13_06fcc928b8e24e429a01d729786a4342.pdf?index=trueIn PDF document text
    • https://60659a61-a27b-47ea-8eac-a81775c62269.filesusr.com/ugd/7a7fb1_2e3df66675c0432baabaf36e61d0571e.pdf?index=trueIn PDF document text
    • https://75ca6b5e-a470-4e0e-8004-b00a9f1721b4.filesusr.com/ugd/1e4819_504f36c8ea844fbf88258c67f59a7a99.pdf?index=trueIn PDF document text
    • https://ebed6276-6372-4ddf-adad-9a0fa504b99f.filesusr.com/ugd/805d2a_4967f3243e8f47e0a1510f72a18316cf.pdf?index=trueIn PDF document text
    • http://buzatagijekoj.rf.gd/nosezexanoxiponewube.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_off0000fb39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB39 5632 bytes
SHA-256: e836d94cca2d3d995e8460b993e83e7a34ceab16bfbc5b07afab813311756d7c
font_01_sfnt_off00010e5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E5D 11252 bytes
SHA-256: 27268cbcbaec84fc14b22e5375776bd2be7b406a211de3a96aed7253907e2fd5

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