Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f033e9b77d95f29…

MALICIOUS

PDF

73.5 KB Created: 2021-09-16 06:01:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 5731fc814183b40f786c2d113583db1c SHA-1: 249a6fff2c224c99cf59e07f17b40c170f7e61a3 SHA-256: 8f033e9b77d95f29a81c1b6775dcb28e6b7f2c93a56aa2eced8614a05effd3b6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ML classifiers and ClamAV, with heuristics indicating it functions as a link farm. Multiple embedded URLs point to compromised CMS uploads and disposable hosting, suggesting an attempt to distribute malicious content or engage in SEO spam. The presence of PDF_URI and PDF_SEO_DISPOSABLE_LINK_FARM heuristics strongly supports this attack pattern.

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
  • 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.chp.pl/ckfinder/userfiles/files/zunaniburega.pdf In PDF document text
    • http://soc-in.com/data/media/files/fetilonisivorubiwezelurem.pdfIn PDF document text
    • https://bda.ch/ckfinder/userfiles/files/xapumefebalarularalezofik.pdfIn PDF document text
    • https://xn--z4qq44i.xn--kpry57d/upload/actfiles/sipaxi.pdfIn PDF document text
    • http://huiking.cn/uploads/file/012103028542.pdfIn PDF document text
    • http://scandirent-new.ru/uploads/assets/file/nazureko.pdfIn PDF document text
    • http://cellesekorea.com/ckupload/files/15036668088.pdfIn PDF document text
    • http://illinoislivestock.org/userfiles/file/resuvajupetimatepevozet.pdfIn PDF document text
    • http://zoldjogsi.hu/uploads/files/63047718462.pdfIn PDF document text
    • http://alompar.hu/uploads/content_files/files/1239162174.pdfIn PDF document text
    • http://peaceinsrilanka.lk/ckfinder/userfiles/files/notowududivomawi.pdfIn PDF document text
    • http://school19-zav.ru/userfiles/file/4207048618.pdfIn PDF document text
    • http://zekidilektekstil.com/images_upload/files/fupuxadotuzuvapilowubilox.pdfIn PDF document text
    • https://tradingphrases.net/userfiles/files/10756150695.pdfIn PDF document text
    • https://rmp-familienanzeigen.de/cms/files/jipapagivemanew.pdfIn PDF document text
    • https://nam.it/wp-content/plugins/formcraft/file-upload/server/content/files/161376dc12a7fd---bunefixaropewurun.pdfIn PDF document text
    • http://kazenergy.kz/wp-content/plugins/formcraft/file-upload/server/content/files/16137938aa9c2b---wezotuwolupirete.pdfIn PDF document text
    • http://debnine.net/UserFiles/File/damojonalemuxafujorututed.pdfIn PDF document text
    • http://duquenne-moteurs.fr/webroot/upload/files/9341354378.pdfIn PDF document text
    • http://efrex.cz/files/file/54477413685.pdfIn PDF document text
    • http://skuplaptop.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16142947d410d8---41568082020.pdfIn PDF document text
    • http://wijnhuis-vaessen.nl/site/data/ws/files/29759874376.pdfIn PDF document text
    • http://xn--76-6kca8aqc6c.xn--p1ai/pic/userfile/63474478530.pdfIn PDF document text
    • http://mazdooradda.com/userfiles/file/21105896621.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=video+da+scaricare+per+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_off0000b5d7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB5D7 19972 bytes
SHA-256: 08dd6b13593a454ad80cd1177efe03cb284569602e42c8db3c261a321be1876a
font_01_sfnt_off0000e981.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE981 10332 bytes
SHA-256: d16c6b2a3c950bcc777e52ea900a10864a5b82c6390b4f9f641ac47e0719d45b
font_02_sfnt_off000100e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100E4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1