Malicious PDF — malware analysis report

Static analysis result for SHA-256 2571d910a1ed25ec…

MALICIOUS

PDF

79.7 KB Created: 2021-09-14 11:15:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: e201b95168b4ee7d886ec7e34fc4812d SHA-1: 60577ceb48b7d0a0a5a515aa1f083163726f4efa SHA-256: 2571d910a1ed25ec2502515d89910845a7208bff8e57459fb4be6eeb099bdf2d
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected by ClamAV as Pdf.Phishing.Trojan and an ML classifier flagged it with high confidence. It contains numerous embedded URLs, many of which point to PDF files hosted on various domains, suggesting a link farm or redirection mechanism. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using disposable hosting for these links, commonly seen in phishing campaigns. Although no scripts were explicitly extracted, the nature of the heuristics and the numerous external links strongly suggest a malicious intent to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 5

  • 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.
  • 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 http://www.norestim.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16138e1cbb3e82---46973622277.pdf In PDF document text
    • https://www.ijdsir.com/ckfinder/userfiles/files/fogag.pdfIn PDF document text
    • https://www.tratedu.net/ssss2018/assets/143ad273/ckfinder/core/connector/php/upload/userfiles/files/5fcfd4a11613532498bc19f52dc2447e.pdfIn PDF document text
    • http://plan.msu.ac.th/ckfinder/userfiles/files/54786505558.pdfIn PDF document text
    • http://remont-etalon.ru/upload/files/2177556178.pdfIn PDF document text
    • http://sromedical.com/file_media/file_image/file/60441994808.pdfIn PDF document text
    • http://krasneclanky.cz/uploads/petasusinawowuropaxojiw.pdfIn PDF document text
    • https://grafconsulting.pl/Upload/file/mejokiwilivovuwimi.pdfIn PDF document text
    • http://studiomontironi.eu/userfiles/files/wafuponolujanijadi.pdfIn PDF document text
    • http://tbff-bygg.se/img/files/bafuxitoraxosasa.pdfIn PDF document text
    • https://ecotranslation.ca/upload/editor/file/fanizojekaluro.pdfIn PDF document text
    • http://tsrmmessina.it/userfiles/files/pudumalazulufikone.pdfIn PDF document text
    • https://qualityroofinnandsuites.com/nbloom/fckuploads/file/paradu.pdfIn PDF document text
    • http://mikailang.com/userfiles/file/20210914094507_1438256257.pdfIn PDF document text
    • http://yepuco.com/uploads/files/niwujifumipesajopibavop.pdfIn PDF document text
    • https://jasmijnbloemengroen.nl/userfiles/file/57758687333.pdfIn PDF document text
    • http://ventexevent.se/uploads/file/guvavanevidegajogaruxojub.pdfIn PDF document text
    • https://postelezmasivu-ostrava.cz/ckfinder/userfiles/files/52682317731.pdfIn PDF document text
    • https://xn--80apefbdm9ah5g.xn--p1ai/userfiles/tisesivoru.pdfIn PDF document text
    • http://www.polni.si/Images/files/tesaluf.pdfIn PDF document text
    • http://gsemilia.it/userfiles/files/48014377424.pdfIn PDF document text
    • http://ng-sons.com/userfiles/file/66595450785.pdfIn PDF document text
    • http://ph-easycome.com/userfiles/file/nafis.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=pronouns+that+start+with+the+letter+tPDF 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_off0000d60e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD60E 10392 bytes
SHA-256: 4ce08a5455ff374e8bc6a646285d52f5069ef861ac3fc4e2d98e7680c06017a6
font_01_sfnt_off0000ed98.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED98 16760 bytes
SHA-256: 39bead83631261f31c159059e446cf6b1568652538dd571ca20a5adc141aecc5
font_02_sfnt_off000118a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x118A9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1