Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f15d82cf942b819…

MALICIOUS

PDF

70.2 KB Created: 2021-09-13 07:27:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: bd749aca99635e5bb98e61daca1d9708 SHA-1: 1e126d783b9804720fd91a8c616b59314b3eacf0 SHA-256: 8f15d82cf942b819c322774db8026ea29d5d98b7bc9317105a6b8a1e365c5611
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The sample is a PDF file flagged by ClamAV as a phishing trojan and by an ML classifier as malicious. It contains numerous embedded URLs pointing to various domains, many of which appear to be compromised WordPress sites used for hosting malicious PDFs. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of using disposable hosting and redirectors, suggesting an attempt to obscure the final malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://smidgel.ru/uplcv?utm_term=varian+pdf+microeconomia PDF link annotation
    • https://readxyz.com/wp-content/plugins/super-forms/uploads/php/files/1610d2dc69dbba055b206b47975d6295/pizevenifakafanogelexon.pdfIn PDF document text
    • http://kuryakyn.ru/userfiles/file/zixigenorimotote.pdfIn PDF document text
    • https://beytarimcilik.com/admin/editor_resim/file/43059611986.pdfIn PDF document text
    • http://yogo110.com/userfiles/file/keveb.pdfIn PDF document text
    • http://geomanteia.com/userfiles/files/35226839334.pdfIn PDF document text
    • http://letresorellebio.it/userfiles/files/wajowibakubuwelaxajinozan.pdfIn PDF document text
    • http://cathyknightwaite.com/ckfinder/userfiles/files/36973404318.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/161304cdded061---zofejevu.pdfIn PDF document text
    • http://iphonedown.com/ckfinder/userfiles/files/49121665552.pdfIn PDF document text
    • http://ziguratex.com/helpdesk/app/webroot/img/userfiles/files/jafamemim.pdfIn PDF document text
    • https://amagi.la/wp-content/plugins/formcraft/file-upload/server/content/files/16133293554d2a---dipilenogogabuxuxutesujox.pdfIn PDF document text
    • http://www.onegelha.com/wp-content/plugins/super-forms/uploads/php/files/f70fc0bf9f8153a997680c3e14c5d974/68145107769.pdfIn PDF document text
    • http://sts-logistika.ru/wp-content/plugins/super-forms/uploads/php/files/9dd83f8b1b1838faa8ef19e36bc37b24/kizodufafagotipugeg.pdfIn PDF document text
    • http://kfbma.org/files/fck/file/90621917338.pdfIn PDF document text
    • https://tiemhoamo.com/data/dulieu/files/jijazogatavubisemita.pdfIn PDF document text
    • http://mikomisushiwc.com/uploads/files/tafonazibop.pdfIn PDF document text
    • http://checopharma.com/upload/files/lidoridunolebelebof.pdfIn PDF document text
    • https://hashtag.school/userfiles/file/96614471230.pdfIn PDF document text
    • http://lnshiyue.com/userfiles/file/20210905121831_1243789649.pdfIn PDF document text
    • http://kieryk.pl/img/userfiles/file/mafivaza.pdfIn PDF document text
    • http://cgpreceptor.com/ckfinder/userfiles/files/zetegebawexajozusafew.pdfIn PDF document text
    • http://mineraux-et-lithotherapie.fr/ckeditor/upload/files/89396771142.pdfIn PDF document text
    • https://coastalholidayproperty.com/ckfinder/userfiles/files/89456424031.pdfIn PDF document text
    • https://gemma.lucien-sv.info/uploads/files/613053be07d57.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_off0000b526.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB526 15152 bytes
SHA-256: dfaaa21baeb664c320f345ec424c395db477173896893a9b9dc68bdaf26c391b
font_01_sfnt_off0000db67.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB67 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f37e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF37E 10440 bytes
SHA-256: 80d64555afcd8ea2bd889de86fa9800f97e648e3eb4623a7bdc6c52fab6c0994