Malicious PDF — malware analysis report

Static analysis result for SHA-256 cd3c259d896d79dd…

MALICIOUS

PDF

134.6 KB Created: 2021-05-10 05:55:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: dd43dd4b9cc394640f57af3b294e2216 SHA-1: e044b34938eec33548ca782446a6c25c66a65bdf SHA-256: cd3c259d896d79dd54e894eef8887880ea4a877bc348231d4f071121567a4aee
126 Risk Score

Malware Insights

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

The PDF file contains a large number of external links to various domains, many of which appear to be disposable hosting. The heuristic 'PDF_SEO_LINK_FARM' indicates a link farm designed for SEO purposes. The ML classifier also flagged this PDF as malicious. The primary intent appears to be directing users to a network of potentially malicious or low-quality content hosted on these external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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.
  • 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://resalured.ru/strik?utm_term=korean+grammar+pdf
    • http://prequester.online/how_to_unlock_lg_ac_remote5bn1k.pdf
    • https://kuzogirig.weebly.com/uploads/1/3/4/7/134748708/wajaxobor.pdf
    • http://indital.fun/1064622692804f5i.pdf
    • http://irisca.online/what_is_an_example_of_compare_and_contrastekcz2.pdf
    • http://triple-doska5.club/jiwotebijakovadufanap1dco.pdf
    • http://piredvizhnik.com/certificate_of_insurance_sampleoqw1i.pdf
    • https://tevufipe.weebly.com/uploads/1/3/1/6/131606546/gorenalomojak_wekugadodet_pilovibivivuwix.pdf
    • https://xalemewo.weebly.com/uploads/1/3/4/6/134665704/fonovuv-gugatim.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/89179faa-da8a-4b56-8df6-ec81dc4ce6ab/kitala.pdf
    • https://uploads.strikinglycdn.com/files/8f2567d4-e25e-46f3-ab3b-3b7e8cd0ca93/28484477604.pdf
    • https://8271b8e8-1520-4b18-8785-2fafc8cd33e6.filesusr.com/ugd/efc97f_b25c92b2919a423eb9661f08b5d97451.pdf?index=true
    • https://cb6d8354-940b-4e05-9f1d-0150973ab277.filesusr.com/ugd/882da0_999658c9188d4a0b9e53ea7a7936d8ff.pdf?index=true
    • https://e82ff0bd-cb1a-4782-8b92-0a0fb7657660.filesusr.com/ugd/d17951_2a985d94a4744b4d8d1971f915d7ddce.pdf?index=true
    • http://ledukuxadom.epizy.com/82745292457.pdf
    • http://wekibanufaminop.epizy.com/modufukowapevak.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

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000129ee.bin
ca954f8427fe8febbfa519b792b03704b4e13bdfcabc83c3ab4000110122763a		 pdf-font-stream PDF embedded font (sfnt) at offset 0x129EE 60672 bytes
font_01_sfnt_off0001ca52.bin
aa715e7d33da936e27a1ed16859fa658bda533769f166a5fb2d602d0444648c3		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1CA52 5120 bytes
font_02_sfnt_off0001dba9.bin
3576dd373b651515f47e23d31ed66261cdf4600bff3365b97b89943213537ffa		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1DBA9 2660 bytes
font_03_sfnt_off0001e714.bin
5fd51dbf2fc586f068c1b3d02596ebe44e44b5c1f84719efa32ebeeef9429524		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1E714 11092 bytes

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