Malicious PDF — malware analysis report

Static analysis result for SHA-256 d855f1a36e1b44ba…

MALICIOUS

PDF

80.7 KB Created: 2021-09-20 16:58:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: d90e43ace25eb0b7a4c23bc2cf24b2c7 SHA-1: 05c9a66d154e58405931b996bf0af2e4d49e9044 SHA-256: d855f1a36e1b44ba594e96a3a279b836c503ab952b1d6d6c937443a594436ee1
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous external URIs, many of which are part of a link farm hosted on disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The embedded JavaScript is a common technique for executing malicious code or redirecting users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 https://medvor.ru/uplcv?utm_term=android+programming+lab+exercises PDF link annotation
    • https://eetravel.net/file/xevigosevebexuxavasefi.pdfIn PDF document text
    • https://all-stage-meditation.tw/uploads/files/61456a80aa3ec.pdfIn PDF document text
    • http://stitesattorney.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/57033683266.pdfIn PDF document text
    • http://autofactory-jin.com/js/upload/files/diterosam.pdfIn PDF document text
    • http://orderkai.com/uploads/files/56640767841.pdfIn PDF document text
    • http://baschin-heizung.com/meineBilderAlbertGrundschule/file/nosafinifofu.pdfIn PDF document text
    • http://www.cerel.eu/images/wyswig_images/file/xanisolixuwovatubotit.pdfIn PDF document text
    • https://www.sir.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16140e9e9bde61---nopofotaduti.pdfIn PDF document text
    • https://uetty.xyz/js/ckfinder/userfiles/files/37260253738.pdfIn PDF document text
    • http://shinserviceodi.ru/wp-content/plugins/super-forms/uploads/php/files/3525044916ff949536bb4ac32caf0ea8/wewedulusuzixi.pdfIn PDF document text
    • http://ttworld.hu/uploads/content_files/files/vexedunuzasesoxopafimu.pdfIn PDF document text
    • https://rosenstein.lu/userfiles/files/83820901637.pdfIn PDF document text
    • http://wingtsunkungfu.ro/imagini_ws/mujinanetivelutenupage.pdfIn PDF document text
    • http://interwork.sk/userfiles/file/javegivujosufalezosotunuk.pdfIn PDF document text
    • http://parkety-patemal.sk/files/file/timanigixezedogeromopax.pdfIn PDF document text
    • http://picart-personal.pl/fckupload/upload/file/rimazul.pdfIn PDF document text
    • http://volkshilfe-vlbg.at/images/content/files/69998926868.pdfIn PDF document text
    • http://geoodwierty.pl/files/file/popidugaxokiratulitisadu.pdfIn PDF document text
    • https://hatinhjobs.com/upload/files/35181389069.pdfIn PDF document text
    • http://www.etoiles-recrutement.com/wp-content/plugins/formcraft/file-upload/server/content/files/161415538c0bf0---guxutowaxokemumedibe.pdfIn PDF document text
    • http://cafesezony.ru/fck_editor_files/files/bovogasigon.pdfIn PDF document text
    • http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16137a1f75ef7b---27918376584.pdfIn PDF document text
    • https://foodsafebox.com/ckfinder/userfiles/files/mokivuxiretopodadatut.pdfIn PDF document text
    • 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_off0000d76f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD76F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ef81.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF81 17564 bytes
SHA-256: ddebcf0116b99ace836c7042629cf12fe3e9d0001aa8f43ab6fc2b33bd25d3f4
font_02_sfnt_off00011d77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D77 10984 bytes
SHA-256: a3df9f8d9fa550495b4b9c8d948fed1b17e81607898f914479be6619ee6e6f63