Malicious PDF — malware analysis report

Static analysis result for SHA-256 877484d74c13fbc9…

MALICIOUS

PDF

88.0 KB Created: 2021-09-10 01:53:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: c85ef21aad90de405d08c03d3fca520c SHA-1: 3ffcb506ab78ebdd85d48d5be8ef150c1f906ce4 SHA-256: 877484d74c13fbc99c1348e7ec9734df8a5fa9a7f19e8bb959db7e8b49a2838d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file identified as malicious by ClamAV and an ML classifier. It functions as a link farm, with numerous embedded URLs pointing to various domains, some of which are associated with compromised CMS uploads. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using disposable hosting for these links. While no scripts were explicitly extracted, the nature of the embedded URLs and the 'link farm' heuristic suggests an attempt to lure users to malicious sites, likely for phishing or to download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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.oteliapelsin.ru/ckfinder/userfiles/files/88408664005.pdf In PDF document text
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613424fd46845---lexazamug.pdfIn PDF document text
    • http://bdnchem.com/upload/files/2828188764.pdfIn PDF document text
    • http://www.childofafrica.org/media/userfiles/file/85675646422.pdfIn PDF document text
    • http://lnv-cnc.gr/userfiles/file/9453332243.pdfIn PDF document text
    • http://elistaprezentow.pl/userfiles/file/94658037094.pdfIn PDF document text
    • http://vincitydata.com/uploads/ckfinder/files/xagilotunufigijij.pdfIn PDF document text
    • https://restaurant-kamkok.fr/img/Data/file/bojudivabarenolig.pdfIn PDF document text
    • http://fcgo.tw/uploadpic/files/69263535139.pdfIn PDF document text
    • https://braindevelopmentmaps-org.neurondevelopment.org/userfiles/files/kodagojoduxidobuzoxetopeb.pdfIn PDF document text
    • https://dunaweb.co/bg_image/files/gilodamisevewararefipesu.pdfIn PDF document text
    • http://xn----7sbabaajmdfbk3ddf3azka3b6a2r.xn--p1ai/ckfinder/userfiles/files/wadodizipexeker.pdfIn PDF document text
    • http://paitoonbox.com/userfiles/files/42216180799.pdfIn PDF document text
    • http://sostrevalli.it/userfiles/files/99936747093.pdfIn PDF document text
    • https://yogaspotny.com/userfiles/file/60188357086.pdfIn PDF document text
    • http://akiisushi.com/uploads/files/95546786661.pdfIn PDF document text
    • http://www.dgtrans.co.th/login/ckfinder/userfiles/files/81160935205.pdfIn PDF document text
    • http://alkanboya.com/files/file///86477188550.pdfIn PDF document text
    • http://careerhack.net/wp-content/plugins/formcraft/file-upload/server/content/files/161341656ae1bb---28534508140.pdfIn PDF document text
    • https://www.fecomerciomg.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/161337808ed637---24894862070.pdfIn PDF document text
    • http://steclotildehorton.ca/wp-content/plugins/formcraft/file-upload/server/content/files/161365f7eabb7c---51906962182.pdfIn PDF document text
    • http://mirutte.com/newsfiles/files/molixutovigenazofuxaxenug.pdfIn PDF document text
    • http://abwlondonblvd.com/uploads/files/gesedikarubazufedu.pdfIn PDF document text
    • http://richardchong.com/userfiles/files/79431351203.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=hazlitt+economics+in+one+lesson+pdfPDF 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_off0000f02c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF02C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010843.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10843 10732 bytes
SHA-256: 07e6c27a51b70bdcf322040b17c08a61b84498874e0fb9633f4def9d318ac866
font_02_sfnt_off000120e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120E1 18888 bytes
SHA-256: a4433f004b6b705577f404e22364beebc1a380166b27c761f72eb73747dd5697