Malicious PDF — malware analysis report

Static analysis result for SHA-256 31f64c638b163d9f…

MALICIOUS

PDF

81.0 KB Created: 2021-10-08 14:11:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 3c4575ce04934991c3948e36fd83b2e3 SHA-1: 8060abf0bc7178060161af7876c3f8e98ce03f4d SHA-256: 31f64c638b163d9f75ed1d90f89880773ca8fe39952fcd2d754bf6c5d9a8081b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs, many of which point to unknown or compromised domains, suggesting a link farm designed to redirect users to malicious content. ClamAV and ML classifiers also flagged this PDF as malicious, specifically as a phishing trojan. The presence of multiple external URIs and link farms indicates an attempt to lure users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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 http://www.alex-vasilkov.ru/images/wisdom/file/4154320763.pdf In PDF document text
    • http://www.asiacoservice.com/file/files/lisaz.pdfIn PDF document text
    • http://elite-nails.pl/Upload/file/95032444223.pdfIn PDF document text
    • https://egc.ecrom.work/syo/files/4280815090.pdfIn PDF document text
    • http://daiichibus.vn/uploads/news_file/vusoduredawexifi.pdfIn PDF document text
    • https://qigoodteam.com/uploads/files/202109260444275167.pdfIn PDF document text
    • http://md-servicios.com/userfiles/file/54714569898.pdfIn PDF document text
    • https://beautifullifeuk.com/wp-content/plugins/super-forms/uploads/php/files/4cd4cca4eaec87ec3ecdeee61312bcbb/revosimukiwemuminel.pdfIn PDF document text
    • http://erpos.sk/data/files/xelobobovirebevewibokeg.pdfIn PDF document text
    • https://www.edmcenter.xyz/ckfinder/userfiles/files/palegogen.pdfIn PDF document text
    • https://smshealthcareservices.com/ckfinder/userfiles/files/13723246368.pdfIn PDF document text
    • http://automyjka.pl/automyjka.pl/userfiles/file/73438047578.pdfIn PDF document text
    • http://gatewayhotelbangkok.com/upfile_hotel/files/piwobiwozuzawede.pdfIn PDF document text
    • https://readxyz.com/wp-content/plugins/super-forms/uploads/php/files/67b2e50a159d25121c7baa0337bc6c31/banotubava.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133613373953---muzibevonubeju.pdfIn PDF document text
    • https://hyosungulf.com/uploads/file/97676856348.pdfIn PDF document text
    • https://appchecar.com/ckfinder/userfiles/files/dikab.pdfIn PDF document text
    • https://hung168.tw/UserFiles/files/janamofilupekefugawikaba.pdfIn PDF document text
    • http://j-line.ca/fck_upload/file/rifepubenitu.pdfIn PDF document text
    • https://keongracun.org/contents/files/vasofufolinelosivapaki.pdfIn PDF document text
    • http://salamino.pl/userfiles/file/66574970089.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=hsc+rearrange+with+answerPDF 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_off0000d814.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD814 18200 bytes
SHA-256: 937a208c4b1b9fdb4237e32de158e06f92f4954ce4e29d72e55d01068c873a88
font_01_sfnt_off00010740.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10740 10420 bytes
SHA-256: e0485f331dbf39bc9c1df8b0020d53ba1828c20cbcfbefa937d8b4a75658f444
font_02_sfnt_off00011eda.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EDA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1