Malicious PDF — malware analysis report

Static analysis result for SHA-256 833efd11899c9daa…

MALICIOUS

PDF

78.4 KB Created: 2021-08-11 22:54:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: bb732de32f012c66fa92a2920b9e4c86 SHA-1: 886c87e238df783986ee1767a81226a664b22eb3 SHA-256: 833efd11899c9daa8d0dafee758049614e89277613f5dc6354e4738bc50c94ca
156 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous embedded URLs pointing to other PDF files hosted on various domains, many of which appear to be compromised. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' suggests these links are designed for SEO manipulation or to obscure the true destination, common in phishing or malware distribution schemes.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://relleno-acidohialuronico.com/wp-content/plugins/super-forms/uploads/php/files/7f8baa360ce09783282942e725374dc1/wilonul.pdf In PDF document text
    • https://fwullong.com/upfiles/editor/files/dawavu.pdfIn PDF document text
    • https://aravlicraft.com/cmsCart//upload/file/1611565717.pdfIn PDF document text
    • http://cephedanismani.com/images/pages/file/gofesewi.pdfIn PDF document text
    • http://amoy-art.com/Upload/file/sidami.pdfIn PDF document text
    • https://hoanghaie.com/Images_upload/files/98385377127.pdfIn PDF document text
    • http://w-f-l.de/user_img/file/2959546974.pdfIn PDF document text
    • https://alarouba.com/ckfinder/userfiles/files/25808904404.pdfIn PDF document text
    • https://atlasautoglass.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606fd47cb42e0---74328784857.pdfIn PDF document text
    • http://lncxjzxxw.com/upload_fck/file/2021-7-10/20210710104846393020.pdfIn PDF document text
    • https://ceadersvalet.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b542f86b46d---12174796931.pdfIn PDF document text
    • https://hitourkorea.com/FileData/ckfinder/files/20210810_A770D0F3B1B59EAE.pdfIn PDF document text
    • https://spencershaulageltd.co.uk/wp-content/plugins/super-forms/uploads/php/files/eca34eaf26f3e37da72c3239dd783064/domalujejurerobuwek.pdfIn PDF document text
    • http://gazosilikatnn.ru/uploads/files/29989816234.pdfIn PDF document text
    • http://svenstavik.com/wp-content/plugins/formcraft/file-upload/server/content/files/160990b0b43451---wawonizugunux.pdfIn PDF document text
    • https://santehsevast.ru/userfiles/files/zinapalurazesafajefe.pdfIn PDF document text
    • http://resortcrimea.com/ckfinder/userfiles/files/92960932648.pdfIn PDF document text
    • http://omonetach.pl/foto/ilustracje/file/jetajutawavigasi.pdfIn PDF document text
    • https://ssmavidiyar.com/public/content-images/files/rapenewube.pdfIn PDF document text
    • https://dfa-finanz.de/wp-content/plugins/formcraft/file-upload/server/content/files/160cfb42b1883d---264975515.pdfIn PDF document text
    • https://uppersanduskyrotary.com/cms/files/File/bulavelagikidolefukafozij.pdfIn PDF document text
    • https://solarconsulting.org/wp-content/plugins/super-forms/uploads/php/files/18afcf29f092cfb44115a784fa3bb11f/26133620688.pdfIn PDF document text
    • http://hzjksj.com/images/upload/File/keloponetemut.pdfIn PDF document text
    • http://ndt-tl.ru/upload/file/lumatuxive.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=dna+mutation+consequences+worksheet+answersPDF 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_off0000ce8c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE8C 16820 bytes
SHA-256: f610cf8a1e0c33a86bc2dee4cacf31a6a5c5de0aa7e6762f28a264c7938556ff
font_01_sfnt_off0000fa18.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA18 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001122f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1122F 10876 bytes
SHA-256: a897b54135c9f36babc0f4bc037fac0146e15d849e2fb0f044f71b629b76fe39