Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f73c624c6e87aa0…

MALICIOUS

PDF

82.0 KB Created: 2021-09-17 07:35:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: a35c3748d214d03bdde8df87fa457f2e SHA-1: 9f6de1269ddb9ad1619f5189e8020ea38e0358ad SHA-256: 4f73c624c6e87aa02cd5ff7203627ec53908b0a1c969583eef3ebc2d18ed9dd1
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple embedded URLs, many of which are algorithmically generated and hosted on disposable domains, indicating a phishing or malware distribution scheme. The ML classifier and ClamAV detection strongly suggest malicious intent. The presence of external URIs and link farm characteristics point towards the document's primary function being to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://chcial.ru/uplcv?utm_term=linux+install+chromebook PDF link annotation
    • http://dainichiji.com/upload_ckr/files/17780430467.pdfIn PDF document text
    • https://eliteplacementagency.com/uploads/files/mewododefurigiridolona.pdfIn PDF document text
    • http://freeorden.com/media/file/donefimumoradetikuj.pdfIn PDF document text
    • http://ambulatorioveterinariovianello.eu/userfiles/files/renisajakivisuruvefekobip.pdfIn PDF document text
    • https://fier-forjat-valimet.ro/ckfinder/userfiles/files/miruzemotajovolezopoxig.pdfIn PDF document text
    • https://piphoto.tw/uploads/files/202109082059173566.pdfIn PDF document text
    • https://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/kf5ooqc46v41fo2km50vr3flne/konexigumoduvaleta.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/tfc9jhaegljuusa4eijdsq40f7/guzuketes.pdfIn PDF document text
    • http://jagdrevier.hu/upload/images/file/36362354924.pdfIn PDF document text
    • http://szintai.hu/ckfinder/userfiles/files/53820267951.pdfIn PDF document text
    • https://festivaldelmaridaje.com/sgi_userfiles/userfiles/files/94632633574.pdfIn PDF document text
    • http://renknh.com/ckupload/files/siwekadixobu.pdfIn PDF document text
    • https://detmers-kontejner.hr/files/29764019534.pdfIn PDF document text
    • http://artpolinakuzina.ru/pict/file/xilemigodufuxegab.pdfIn PDF document text
    • https://stotex.rs/files/balenuvoliladefiwuketexo.pdfIn PDF document text
    • https://mimpidia2.com/contents/files/dotefuzasomoxevarewezoni.pdfIn PDF document text
    • http://kalmi.ru/upfiles/files/21134078520.pdfIn PDF document text
    • http://bancasemecanino.com/userfiles/files/77645170729.pdfIn PDF document text
    • http://tractortools.cz/ckfinder/userfiles/files/5461220556.pdfIn PDF document text
    • http://eternaseguros.net/files/files/54444450971.pdfIn PDF document text
    • http://gaytonfa.com/upload/files/58196208996.pdfIn PDF document text
    • http://skazka76.ru/pic/userfile/5732767702.pdfIn PDF document text
    • https://cottonweb.net/userfiles/file/33632404840.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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dfc6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFC6 16072 bytes
SHA-256: f0a7b970aba23fdf0aebd4a4d58f7b14b5b4a2f46606bddf764a8c1659b57455
font_01_sfnt_off00010923.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10923 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001213a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1213A 10884 bytes
SHA-256: f190565415ddd7a64a4baf326c093c98f42e6cba4b812ed798eedf4d637e3cab