Malicious PDF — malware analysis report

Static analysis result for SHA-256 da6e1b78faec375c…

MALICIOUS

PDF

80.2 KB Created: 2021-09-10 13:11:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: ef93b7554c9efcce6c99d8ca80c2aa6a SHA-1: e5e5d970315cd1f32a843bfb426a2ea23fca4634 SHA-256: da6e1b78faec375ce9c4ac250202893621094b494fb9e8f094dc3991bc5d28ed
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The sample was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier as malicious. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to other PDF files hosted on various domains. The primary purpose appears to be SEO poisoning or distributing further malicious content through a network of linked PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.slenderclub.cz/ckfinder/userfiles/files/45705366426.pdf In PDF document text
    • https://bouveau-consulting.com/userfiles/file/bigojelonod.pdfIn PDF document text
    • http://yuqiaohome.com/uploads/files/202109091405026756.pdfIn PDF document text
    • https://www.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1613510da09d04---57313902169.pdfIn PDF document text
    • https://solelane.com/ckfinder/userfiles/files/sizexarogoxaxitotagapewav.pdfIn PDF document text
    • http://vitrine-prof.com/files/53767442962.pdfIn PDF document text
    • https://jancsoalapitvany.hu/ckfinder/userfiles/files/61335016422.pdfIn PDF document text
    • https://parisnordmedical.fr/docs/file/98582807100.pdfIn PDF document text
    • http://backupcenters.com/userfiles/file/majepepen.pdfIn PDF document text
    • https://emilline.dk/ckfinder/userfiles/files/9447451189.pdfIn PDF document text
    • https://grafconsulting.pl/Upload/file/geguwusozifid.pdfIn PDF document text
    • https://amadesafar.ir/basefile/amadesafarir/files/3637416003.pdfIn PDF document text
    • http://turbotechnik24.de/userfiles/file/27838896192.pdfIn PDF document text
    • https://saglamahsapkutu.com/img/editor/image/file/74292033670.pdfIn PDF document text
    • http://topimmigrationlawyer.org/ckfinder/userfiles/files/puzufadebopetipizu.pdfIn PDF document text
    • http://bantinnhadat.com/users/files/8013377170.pdfIn PDF document text
    • https://afmiletisim.afmiletisimajansi.info/resimler/files/43754915502.pdfIn PDF document text
    • https://mattress-leader.com/media/lituzedejeb.pdfIn PDF document text
    • http://vagtteam.dk/userfiles/Files/kabasepivivagenef.pdfIn PDF document text
    • http://www.nationaalgolfcongres.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161378e5f89af6---repaguwaverawazoleb.pdfIn PDF document text
    • http://gvs-russia.ru/admin/ckfinder/userfiles/files/3572563330.pdfIn PDF document text
    • http://mayingiabao.com/upload/files/3901242085.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=manual+call+recording+app+for+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_off0000d655.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD655 10624 bytes
SHA-256: 701f958821fe6ccf6f109356923661c5d5837a3fbbb4278207796a42ca937bc9
font_01_sfnt_off0000ee78.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE78 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001068a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1068A 17156 bytes
SHA-256: 4155e5e07e4b781f675e96892c37332c99b4e9a262a1c6228ee5ab432294ac80