Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f5b4246e9e5979c…

MALICIOUS

PDF

81.3 KB Created: 2021-08-26 03:16:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 8b22140a3a153076eccc7f8a6c8e8ef8 SHA-1: 303af4101a235ed1637d6cac0e99ab00f45fff1d SHA-256: 4f5b4246e9e5979ca684a3882badb92b99d8f869b1c10b9747fab9330a66fc22
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of embedded URLs, many of which point to compromised WordPress sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware delivery through these links. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://infrive.ru/uplcv?utm_term=down+to+earth+gower PDF link annotation
    • http://andreevmag.com/wp-content/plugins/super-forms/uploads/php/files/6ee6d0e35126c816e8d133d1ac56c16b/3823138337.pdfIn PDF document text
    • https://thic.net/plugin/ce1/ckfinder/userfiles/files/43128229360.pdfIn PDF document text
    • http://2016montemayorreunion.com/clients/e/e5/e530e98a7ee505477716bae2fe71cdef/File/vukujibenuwulisaxemin.pdfIn PDF document text
    • https://www.elshandmadedesign.nl/ckfinder/userfiles/files/86978344580.pdfIn PDF document text
    • http://prestizhstroycompany.ru/SITE/files/editor/file/28323127018.pdfIn PDF document text
    • https://avayemehr-carpet.ir/data/file/33849938036.pdfIn PDF document text
    • https://monuments-msk.ru/wp-content/plugins/super-forms/uploads/php/files/5ad197dcf44759f87b7036fb998631aa/19934532453.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/h4q4jlr465s1nvr39fj98te262/podexata.pdfIn PDF document text
    • http://ttworld.hu/uploads/content_files/files/sorefivapipiwejibajafew.pdfIn PDF document text
    • https://hiddencliff.kr/FileData/ckfinder/files/20210615_2B65D203CBAC880D.pdfIn PDF document text
    • http://speckrepeg.by/UserFiles/files/18644697174.pdfIn PDF document text
    • http://epoxidice.ro/mm/file/katazanerufojag.pdfIn PDF document text
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/bf0d0580a40daf1fff71d83efe5b7908/13316577914.pdfIn PDF document text
    • http://cz-synergy.cz/data/file/gazijitivolavexutafum.pdfIn PDF document text
    • http://www.orhancoskun.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d43b1e455d---wetumakerol.pdfIn PDF document text
    • http://atsrealtyvietnam.com/upload/files/fejogilo.pdfIn PDF document text
    • https://bbensonmft.com/wp-content/plugins/super-forms/uploads/php/files/a7974abb776b6af35c08d1891b3c0f00/xixasunevavawupi.pdfIn PDF document text
    • https://travelworld.ro/userfiles/file/pesominajasowus.pdfIn PDF document text
    • https://alternativecarrepair.com/userfiles/file/sinakalidegujomifo.pdfIn PDF document text
    • http://www.mtpartnersfl.com/wp-content/plugins/formcraft/file-upload/server/content/files/16089877dcc3ba---34270525723.pdfIn PDF document text
    • http://sosnovgeo.ru/userfiles/file/55306937717.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_off0000dc9a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC9A 10168 bytes
SHA-256: 0ca06ada28c1d20b1da4c5f96b9de0989b45ead232cbe05a13462697e206ff9b
font_01_sfnt_off0000f35f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF35F 16776 bytes
SHA-256: 387d68ad42286e879340d59deb527e5779e7d5b08d8c8656124af06f9c3f488e
font_02_sfnt_off00011ecf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11ECF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1