Malicious PDF — malware analysis report

Static analysis result for SHA-256 4807711815b9d8d7…

MALICIOUS

PDF

98.5 KB Created: 2021-09-17 08:30:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 686a78f35f16329311a911d2b34e3063 SHA-1: 57a533291b456c4f922584efe29558abbafeafea SHA-256: 4807711815b9d8d7aa62eef1b48665d13c1b442625f9f0fa6f0cdd864920a63a
156 Risk Score

Malware Insights

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

The sample is identified as malicious by ML classifiers and ClamAV, indicating it's a phishing or trojan PDF. It contains numerous embedded URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this attack pattern. No scripts were extracted, but the primary function appears to be user redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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://cructi.ru/uplcv?utm_term=applications+of+machine+learning+pdf PDF link annotation
    • http://feach.ie/images/uploads/file/tegunebozodotapomom.pdfIn PDF document text
    • http://studiotecnicopinto.it/userfiles/files/68535062023.pdfIn PDF document text
    • https://willes-gb.com/uploads/files/202109141022345687.pdfIn PDF document text
    • https://emotionalgift.com/ckfinder/userfiles/files/sidomolevonafegogij.pdfIn PDF document text
    • http://podlahyadvere.sk/editor_uploads/system/files/relapeve.pdfIn PDF document text
    • https://sistemagestiondpr.co/userfiles/file/55710528724.pdfIn PDF document text
    • http://getawaynewzealand.co.nz/wp-content/plugins/formcraft/file-upload/server/content/files/1613c3cac96aba---4170951921.pdfIn PDF document text
    • http://vinhhangvien.com/upload/files/93045738810.pdfIn PDF document text
    • https://bfull.ru/uploads/files/55396966976.pdfIn PDF document text
    • http://www.ctnphrae.com/ckfinder/userfiles/files/naditirebulodixapet.pdfIn PDF document text
    • http://kartinatv.org/uploads/files/4373294013.pdfIn PDF document text
    • http://levant-tekstil.com/other_files/File/nuxitijufitovisipeladej.pdfIn PDF document text
    • http://fitviewer.de/files/file/xopovijobofoxeb.pdfIn PDF document text
    • http://tfe-design.dk/userfiles/file/67836139623.pdfIn PDF document text
    • https://kanat.com/upload/ckfinder/files/38192493231.pdfIn PDF document text
    • http://ceroki.com/image/files/41244077409.pdfIn PDF document text
    • http://fruhmann-elektrotechnik.at/53398195910.pdfIn PDF document text
    • http://propertiesforrent.com/userfiles/file///60146920680.pdfIn PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613d7029cbd80---vovowajomokakejatufenubam.pdfIn PDF document text
    • https://www.ccps.mx/wp-content/plugins/super-forms/uploads/php/files/c9d5bf63b969e594dcb5afa234b21228/pijosamowanidimoruw.pdfIn PDF document text
    • http://objetivovender.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613437ab4c06b---4984261109.pdfIn PDF document text
    • http://mimarkamilozkartal.com/userfiles/files/5672044570.pdfIn PDF document text
    • https://108pizza.pl/uploads/userfiles/files/gupakasizugedi.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_off0001178d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1178D 19672 bytes
SHA-256: e38d85a53e1b05d1e20cf006967fa428e39ea834525ec3ea608ab031513837f5
font_01_sfnt_off00014af8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14AF8 11048 bytes
SHA-256: acc067e440d7b2727b77a1a32308d10f0d13f8b9b1c0e826fb5b44fbcc7cba71
font_02_sfnt_off00016452.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16452 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1