Malicious PDF — malware analysis report

Static analysis result for SHA-256 cdf0c91074a4d7a3…

MALICIOUS

PDF

157.0 KB Created: 2021-10-15 00:15:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 6e866366a71f4a22e1eea7982e605690 SHA-1: 8fc96fb88257f6962f328681d82d7266b03a5b50 SHA-256: cdf0c91074a4d7a30f41b58714fc61ccf26bc2303763de685c3d074b672488da
156 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. It functions as a link farm, with multiple embedded URLs pointing to various domains, including one hosted on a compromised WordPress site. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9983

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 https://himalayanwanderer.com/himalayan/userfiles/files/gufoxakakorotibafafebiru.pdf In PDF document text
    • https://www.utn.ac.cr/sites/default/files/files/modazudukapowonikop.pdfIn PDF document text
    • https://ooobelkom.ru/ckfinder/userfiles/files/mewazexanavurexifo.pdfIn PDF document text
    • http://gocoachfox.com/userfiles/file/jedudugeminowinax.pdfIn PDF document text
    • https://goldmenu.com/userfiles/file/wavexurivewepuloze.pdfIn PDF document text
    • http://vegman-kzn.com/ckfinder/userfiles/files/xivavulaposuxubodi.pdfIn PDF document text
    • http://carmakers.cz/userfiles/files/titubaxejuranujov.pdfIn PDF document text
    • https://pulsekb.ru/admin/ckfinder/userfiles/files/1952123522.pdfIn PDF document text
    • http://ipublicity.cz/data/file/gazosobafodunemud.pdfIn PDF document text
    • http://bukharasuwanee.com/sites/default/files/file/98884016235.pdfIn PDF document text
    • http://moscowfashion.net/content/xuploadimages/file/pefabibivagabupo.pdfIn PDF document text
    • https://betenagro.com/sites/default/files/file/71283183879.pdfIn PDF document text
    • http://dolphinegypt.net/userfiles/file/dapopokib.pdfIn PDF document text
    • http://clearlakesd.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613dca75416e0---mumem.pdfIn PDF document text
    • https://primeodontorj.com/wp-content/plugins/super-forms/uploads/php/files/1ca634bb5698cc5d799097b4b8c69d01/30761829438.pdfIn PDF document text
    • http://tensoinox.com/userfiles/files/debizefom.pdfIn PDF document text
    • http://ahkjt.com/upfile/file/59708642755.pdfIn PDF document text
    • https://leciv.fr/uploads/FCK_files/file/rimum.pdfIn PDF document text
    • http://adhdadvisory.com/wp-content/plugins/formcraft/file-upload/server/content/files/16151efb94c988---24232681987.pdfIn PDF document text
    • https://ripedesign.com/app/webroot/files/fckeditor/file/jogefidaforeruzadu.pdfIn PDF document text
    • https://gsacademy.ge/uploads/files/24936831078.pdfIn PDF document text
    • http://volareinmongolfiera.it/userfiles/files/buzezejolilajefenu.pdfIn PDF document text
    • http://feedproxy.google.com/~r/Xvkpad/~3/TSvcnjQ06Jg/uplcv?utm_term=2nd+trimester+meansPDF 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_off00020249.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x20249 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00021a5b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x21A5B 20312 bytes
SHA-256: 8da656f5d21e66a2cd7925b5351c090d9f6e4b8120835804fdf5721cb4eba06e
font_02_sfnt_off00024f2a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x24F2A 10268 bytes
SHA-256: 6cfd01413d44ef4da884356501283799e048aace3ceaa7239787be64680ce7d1