Malicious PDF — malware analysis report

Static analysis result for SHA-256 55731fb4e60b9cb6…

MALICIOUS

PDF

80.8 KB Created: 2021-09-15 20:05:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 6223224532bd39afcdf73ef6b2558e9c SHA-1: 839dff471d5496065d885d7bd796a598d210abe4 SHA-256: 55731fb4e60b9cb692b16dbde68c25d5e011b4383f46bf018fc86278b68b20bf
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The PDF contains numerous embedded URLs, many pointing to other PDF files on distinct domains, characteristic of a link farm used for phishing or malware distribution. The 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic further supports this, noting a high number of distinct hosts and a redirector pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://thenext.pk/userfiles/files/30967728919.pdf In PDF document text
    • http://paulgraphics.paulsfashion.in/files/9034362557.pdfIn PDF document text
    • https://hkfew.org.hk/ckfinder/userfiles/files/setefopenaxarojo.pdfIn PDF document text
    • http://ex2010.com/uploadfile/file/2021091109235373499.pdfIn PDF document text
    • https://ekoelprom.pl/public/images/editor/file/bosupafamolubumora.pdfIn PDF document text
    • https://nibrasimansch.com/userfiles/files/71206521954.pdfIn PDF document text
    • http://avandcie-energy.com/ckfinder/userfiles/files/48419850024.pdfIn PDF document text
    • http://safetruck.gr/images/file/riwudedukopadefotidu.pdfIn PDF document text
    • http://jumpstart.mobi/userfiles/file/22425809783.pdfIn PDF document text
    • http://scea.edu.mn/ckfinder/userfiles/files/demewilitojivelubo.pdfIn PDF document text
    • http://captainkillmite.com/uploads/files/202109090820422008.pdfIn PDF document text
    • https://jordan.si/dokumenti/file/birarufeluligifozelaxi.pdfIn PDF document text
    • http://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16140c3778fd67---jijifafexadijonilol.pdfIn PDF document text
    • http://yusungchart.com/userData/board/file/19280614213.pdfIn PDF document text
    • http://yung-shun.com/userfiles/file/4100918874.pdfIn PDF document text
    • https://immsac.pe/sgi_userfiles/userfiles/files/wopadi.pdfIn PDF document text
    • http://kondicionery-dolgoprudny.ru/upload_picture/file/65151911006.pdfIn PDF document text
    • http://sicompk.com/survey/userfiles/files/juworeziral.pdfIn PDF document text
    • http://files.ibiza-ferien.de/file/28075644445.pdfIn PDF document text
    • https://artofsurfing.com/preview/ckfinder/userfiles/files/69180807404.pdfIn PDF document text
    • https://thebookonpersonaltransformation.com/FCKeditor/file/26621775459.pdfIn PDF document text
    • http://www.studiolegalefusimorelli.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e760733274---verosojixidego.pdfIn PDF document text
    • http://1night2day.com/UserFiles/file/9813699845.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=goosebumps+welcome+to+dead+house+read+online+freePDF 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_off0000d485.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD485 11248 bytes
SHA-256: 4e2f6054bfdc4bbfb35d90597288d30f5e426c552d3040f440142fbafcfcc895
font_01_sfnt_off0000ee8f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE8F 18248 bytes
SHA-256: 1e57bb18234bf280ab365ad25593a342225af22d4cbf5eb64379b94e78863d48
font_02_sfnt_off00011d5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D5D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1