Malicious PDF — malware analysis report

Static analysis result for SHA-256 d55f87ddaf25038b…

MALICIOUS

PDF

72.1 KB Created: 2021-09-18 12:28:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: cbfc25cc9d1b7fc3eaf8295db8695849 SHA-1: 0b8fc1a225d2fd8c458ed8f51beb8a13f356d112 SHA-256: d55f87ddaf25038b5e3d335bb4b0f5d51cfb29e0afda04513670c7f7f7ec4677
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and multiple external URIs, with several heuristics indicating a link farm pointing to compromised WordPress upload storage. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware via the linked PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 7

  • 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.
  • 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 http://bertoniamministrazione.it/bertoni/public/file/dodulevebalogonurizobij.pdf In PDF document text
    • http://www.gainerwindows.ca/wp-content/plugins/super-forms/uploads/php/files/l3b0t77h353kbv2mb5t6grd112/numezukirun.pdfIn PDF document text
    • https://indobaliart.com/sitefiles/file/soresuxigalulibitaziduzu.pdfIn PDF document text
    • http://elementsgogreen.com/userfiles/file/kupatumu.pdfIn PDF document text
    • http://www.linkkorea.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/161412177c9e3a---38907033126.pdfIn PDF document text
    • http://school19-zav.ru/userfiles/file/juxigaxup.pdfIn PDF document text
    • https://pecsikult.hu/files/file/92893742156.pdfIn PDF document text
    • https://marupyara.com/fotos/userfiles/file/rizag.pdfIn PDF document text
    • https://madame-tina.com/ckfinder/userfiles/files/57770951564.pdfIn PDF document text
    • http://www.anapharmata.hu/ckfinder/core/connector/php/files/81059239093.pdfIn PDF document text
    • http://www.39koratmachinery.com/file_upload/files/38604021439.pdfIn PDF document text
    • http://anthonyvienna.com/sites/default/files/file/xotodufaxi.pdfIn PDF document text
    • https://maviet.vn/upload/files/17824393495.pdfIn PDF document text
    • http://serendipityorlando.com/wp-content/plugins/formcraft/file-upload/server/content/files/161424e3e91702---80865430034.pdfIn PDF document text
    • http://gzsjlt.cn/userfiles/file/miviworotex.pdfIn PDF document text
    • http://bloemenwinkelindex.nl/images/uploads/30301360067.pdfIn PDF document text
    • http://www.aaar.cat/assets/js/ckfinder/userfiles/files/68831027191.pdfIn PDF document text
    • http://xn--b1adbbbaeqjtsflbfms0e.xn--p1ai/pict/file/83268743812.pdfIn PDF document text
    • http://dulichtantai.com/files/uploaded/files/55612778465.pdfIn PDF document text
    • http://artgrafika.cz/userfiles/file/lixijelatigika.pdfIn PDF document text
    • https://bhsbeacon.com/FCKeditor/file/5278796344.pdfIn PDF document text
    • http://wxeina.com/userfiles/files/wukos.pdfIn PDF document text
    • https://tallerescarrion.com/uploads/file/webojanavat.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=private+viewer+igPDF 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_off0000b454.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB454 18324 bytes
SHA-256: 6b247d582526f95e6cc1df24f8800dafdb2da697ae1db560d9f7bbd6cd99619c
font_01_sfnt_off0000e480.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE480 9996 bytes
SHA-256: 27eeced8319ae117f4f268439e6e2befaea3e96d7e1338623171f3ed8bc6b837
font_02_sfnt_off0000fadc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFADC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1