Malicious PDF — malware analysis report

Static analysis result for SHA-256 21a853c643510b9f…

MALICIOUS

PDF

75.6 KB Created: 2021-09-04 17:15:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 0defb58dfd2e045b9d574e2b747d2114 SHA-1: 3f0819c900569a196e75c27083d5129a7e39c2d0 SHA-256: 21a853c643510b9f77da5571cedaa818c424e0fa31a0dc266feb042a54673e59
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is a PDF containing a large number of external links, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to distribute malicious content or phish users. The ClamAV detection and ML classifier strongly suggest malicious intent. Although no scripts were explicitly extracted, the nature of the links and the PDF structure are indicative of a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9827

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 farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://coretry.ru/uplcv?utm_term=i+like+chopin+piano+sheet+pdf PDF link annotation
    • https://paron-rebondir.com/uploads/files/juvub.pdfIn PDF document text
    • https://t2sc.me/userfiles/rosaniretubigaran.pdfIn PDF document text
    • https://vaytieudungtragop.com.vn/wp-content/plugins/super-forms/uploads/php/files/uljek6iomb7omoqt0sfiaas7eo/nutuxisubekimel.pdfIn PDF document text
    • http://high-keenltd.com/userfiles/file/guludosajimipojig.pdfIn PDF document text
    • https://www.varisistanbul.com/wp-content/plugins/formcraft/file-upload/server/content/files/160792afb25f61---wudijunirifazofadudipog.pdfIn PDF document text
    • https://isosklo.cz/uploads/lenorapowubimefubifek.pdfIn PDF document text
    • http://safetyassessmentsolutions.co.uk/ckfinder/userfiles/files/34267098664.pdfIn PDF document text
    • http://ituor.ir/basefile/chartermeinfo/files/duxoverixasifol.pdfIn PDF document text
    • http://wksx.top/images/userfiles/file/winaxibevizejolesewexanon.pdfIn PDF document text
    • https://popcouncilinstitute.org/wp-content/plugins/super-forms/uploads/php/files/6725fdc721c935ba51fe9af1bc7ff148/teragu.pdfIn PDF document text
    • http://lorofilmes.com/Uploads/ckfinder/userfiles/files/jifagiso.pdfIn PDF document text
    • http://www.ponderosafestival.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b8aff2144fc---wotudosuwotesixowela.pdfIn PDF document text
    • https://keralatemples.info/ckfinder/userfiles/files/fudog.pdfIn PDF document text
    • http://alemotta.com/resources/original/file/6431744819.pdfIn PDF document text
    • http://hosungtour.net/FileData/ckfinder/files/20210904_494311BE277067D4.pdfIn PDF document text
    • http://dyglas.com/userData/board/file/5752312249.pdfIn PDF document text
    • http://www.nuricomuvakfi.org/wp-content/plugins/super-forms/uploads/php/files/lgn9pm4bqllchanu5llnjol636/lutodupekuw.pdfIn PDF document text
    • https://kildevangen.dk/files/28740808364.pdfIn PDF document text
    • https://cursosadistanciayonline.com/medios//files/tobejosot.pdfIn PDF document text
    • http://erictex.com/ufiles/files/99403944927.pdfIn PDF document text
    • http://111-orte.de/testarea/cwsCMSlight/media/files/xajapowobatevi.pdfIn PDF document text
    • https://masterpieces-mallorca.com/wp-content/plugins/super-forms/uploads/php/files/74efcb63b0e6980550ec5146349d6a1b/jegujazotujedugevuragawom.pdfIn PDF document text
    • https://bluebeakbranding.com/wp-content/plugins/super-forms/uploads/php/files/9e3321d732681041cb14ed3226e01fb5/jigipuxaxerutorulojeborip.pdfIn PDF document text
    • https://obermeyer-modemarkt.de/upload/file/folukozagikinudazuvate.pdfIn PDF document text
    • http://ar-intl.net/wp-content/plugins/super-forms/uploads/php/files/pn01c39a4nt4eod8eut69f0ul6/tewinijego.pdfIn PDF document text
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/16076ead7a4b33---4938085544.pdfIn PDF document text
    • http://www.guus.edu.mn/ckfinder/userfiles/files/xemotekaxomasovajikevedeb.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_off0000c2f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC2F0 10660 bytes
SHA-256: 71e974311915dcb008cc89f35f9b6e8c30e2b9040c5b7e75c37c90e386bcf3b3
font_01_sfnt_off0000db49.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB49 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f35b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF35B 17276 bytes
SHA-256: adb65735d067eb13e6b24eb4f3016f9571bebfa08360d0c7767922bb5312d79d