Malicious PDF — malware analysis report

Static analysis result for SHA-256 898c5af527fd77ce…

MALICIOUS

PDF

82.1 KB Created: 2021-09-21 19:53:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 6ad3a3e4989cf7da063469c626a86979 SHA-1: ef0b7ef5c381664b1470cd9a395eb1b00b1ee077 SHA-256: 898c5af527fd77ceb9df81e368c83c73e71240463de874f051cf0457e7a9a508
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and an ML classifier, with a critical heuristic firing for PDF_JS indicating embedded JavaScript. This JavaScript is likely responsible for the redirection to external URLs, as suggested by the PDF_SEO_DISPOSABLE_LINK_FARM heuristic which identified a large number of links on disposable hosting. The embedded JavaScript is the primary mechanism for executing malicious actions within the PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://kmkmekanik.com/upload/ckfinder/files/4774511906.pdf In PDF document text
    • http://pmrs.ps/userfiles/file/35315990581.pdfIn PDF document text
    • http://bijverhoeven.nl/uploads/files/tevaloxezaxotetekone.pdfIn PDF document text
    • https://tekartltd.com/upload/files/gupikonavewax.pdfIn PDF document text
    • http://dogable.de/userfiles/file/68437083034.pdfIn PDF document text
    • https://learn-atdi.com/uploads/files/rowakebemomobepalafelig.pdfIn PDF document text
    • https://manage4.realtourvision.com/rtv/ckfinder/userfiles/images/files/bofipezineluwumezo.pdfIn PDF document text
    • http://eko-baby.ru/userfiles/file/32283325965.pdfIn PDF document text
    • http://s8radziejowice-paszkow.pl/userfiles/file/71887582615.pdfIn PDF document text
    • http://svazekobciorlice.cz/userfiles/file/60651136772.pdfIn PDF document text
    • http://locthanhroyal.com/upload/files/riraf.pdfIn PDF document text
    • http://ar-intl.net/wp-content/plugins/super-forms/uploads/php/files/jso5qrlv7hm9485dnl1afo1fm7/podupekuropozalujumanak.pdfIn PDF document text
    • http://ekvatorbl.com/userfiles/file/fidaxakojuvosinel.pdfIn PDF document text
    • http://mutitar.com/user_img/files/kumugumuxafemunofoto.pdfIn PDF document text
    • http://arrhythmiaclinic.com/userfiles/file/20210907062002.pdfIn PDF document text
    • http://koyomisushi.com/uploads/files/sinuvul.pdfIn PDF document text
    • http://blow-w124.com/js/upload/files/41644533741.pdfIn PDF document text
    • http://casier-a-bouteilles.com/file/kebavosugotebibeg.pdfIn PDF document text
    • http://conomiya.com/images/uploadedimages/file/juzotivol.pdfIn PDF document text
    • https://pharma-tools.eu/galeria/file/84240594440.pdfIn PDF document text
    • http://mn-print.ru/ckfinder/userfiles/files/xirujovoni.pdfIn PDF document text
    • https://handinhand-daycare.com/ckfinder/userfiles/files/zipixunebedo.pdfIn PDF document text
    • http://elementsgogreen.com/userfiles/file/68883819920.pdfIn PDF document text
    • https://trade.inter-ural.ru/ckfinder/userfiles/files/kefozotixuga.pdfIn PDF document text
    • https://ratsimae.ee/media/contents/file/61855334679.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=editing+contacts+on+androidPDF link annotation
    • 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_off0000dfcf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFCF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f7e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7E1 16892 bytes
SHA-256: 93de99e149b4a099eb7bb5c6041ca455d9cdbb0fe338db61f9ead9278c1aa3e7
font_02_sfnt_off000123db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123DB 10348 bytes
SHA-256: 0d466716d9f2f469cdfa93de5058ec72df97cb7d7c7c5925a20f16f1c00a52cd