Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f5af157877ad1dd…

MALICIOUS

PDF

76.8 KB Created: 2021-04-09 10:17:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: bc8705f03d4b66bd8185e0d0171135df SHA-1: af99c1624c316914104a8822b25062d0fe70c6bf SHA-256: 4f5af157877ad1dd507b147d1efd05a73dd88fe6b4c4c125a28c6cf4c9002095
186 Risk Score

Malware Insights

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

This PDF document was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, embedding numerous external URLs, with a primary focus on 'jottigo.ru'. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, and the presence of external links points towards a phishing or content-farming attack vector. No scripts were extracted from this sample.

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://jottigo.ru/strik?utm_term=how+to+find+z+score+on+standard+normal+table PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4447658/normal_6059105742b6a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4461744/normal_6022bae62efd9.pdfIn PDF document text
    • http://skameyki.club/application_form_for_nsfas_2020bg587.pdfIn PDF document text
    • http://vvvvvvvvvvvvvvvvvvvvvb.xyz/30652287770y7597.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4454277/normal_604fc7f510231.pdfIn PDF document text
    • http://thesimplycompleteseries.com/sample_argumentative_essay_in_apa_formatc8lpq.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4478687/normal_60137fd29d4e4.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4410727/normal_60420876121bb.pdfIn PDF document text
    • http://biomaniix.website/5521510041517jeh.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/a049c9eb-f095-4a1d-b394-ebf2c5ef4eed/taylor_swift_fearless_album_download_deviantart.pdfIn PDF document text
    • https://fa53e508-d88d-41cb-897c-7a5b6f1bfcc3.filesusr.com/ugd/361045_d6d7ff0b39264147a28032ba8f296306.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/7ef8a655-7431-4de4-b3fb-647b25302512/53882324879.pdfIn PDF document text
    • https://121f8fc1-d270-4171-a721-8ccd656fc20f.filesusr.com/ugd/2ca22b_43756d5ab7b94951ad0b837db78f9b68.pdf?index=trueIn PDF document text
    • https://368af19b-b9be-4417-8ea7-dfc4611f9fec.filesusr.com/ugd/abd4c0_b9568a4a064a4fc5985bc58cee4c2a85.pdf?index=trueIn PDF document text
    • https://2e4d99de-9d37-4ce2-abd5-0bbccafdbe51.filesusr.com/ugd/33a2e4_705e31f084374b00b74fca193a2cab0c.pdf?index=trueIn PDF document text
    • https://af18ad75-7652-4b25-b9e0-8da5fded0af1.filesusr.com/ugd/529385_8c4d08029d904e9fb844893ffa719e20.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/31059d55-e98c-4f8d-97da-c7fd4a4f194d/62397206829.pdfIn PDF document text
    • https://33c7e2ec-32fc-4676-a642-9d95a4379e01.filesusr.com/ugd/622218_912dd5f4ad934580936b79537dcdf8fc.pdf?index=trueIn 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_off0000ed39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED39 5408 bytes
SHA-256: 7db489b6dd9d5e5b9cb5ac1cf76f7e9c09bb1dae90b1bc2ddae707f79da04aa3
font_01_sfnt_off0000ffa2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFA2 11184 bytes
SHA-256: 65dc33990a7ba118e0574b0f1c61f5376b11950d858facc4b4413a98fcb890c2