Malicious PDF — malware analysis report

Static analysis result for SHA-256 9b55f8dedec627f4…

MALICIOUS

PDF

72.7 KB Created: 2021-09-06 11:05:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: afadeaac201d4a53986bacef7563d7b3 SHA-1: c476c97091392cd130601dab1628a6b10b1976ca SHA-256: 9b55f8dedec627f4fd60edc30945ec611743d54a27f96479d897dfd28bb3f576
156 Risk Score

Malware Insights

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

The sample is a PDF file identified as malicious by ML classifiers and ClamAV. It contains a link farm pointing to multiple compromised CMS upload directories, suggesting an attempt to obscure the true destination. The presence of numerous external URIs and the 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic indicate a pattern of redirecting users through potentially malicious sites. The document body is heavily obfuscated and unreadable, providing no direct content-based clues.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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 http://brukbet.com/user_images/file/87764067880.pdf
    • http://call.ae/wp-content/plugins/formcraft/file-upload/server/content/files/16075026830cfe---motes.pdf
    • https://apoc.com.au/wp-content/plugins/super-forms/uploads/php/files/facb5332e3c349b63674bd6c86c470f2/zidolaxamu.pdf
    • http://www.pilonidalsinus.gen.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1607718c77a4d7---2729469047.pdf
    • https://gresathouse.com/wp-content/plugins/super-forms/uploads/php/files/18b8983fc01dbe65d80253aca4ffe39c/85445068066.pdf
    • http://kiiga.ru/userfiles/file/pofosor.pdf
    • http://ledseoul.com/userData/board/file/nazazafilutafevozibesinu.pdf
    • https://vinisfarm.com/wp-content/plugins/super-forms/uploads/php/files/4cedf0ba14022f45803cfb17c35a9c13/kobelubojitenoxumelu.pdf
    • https://pui-vital.ro/msg_media/file/1487004937.pdf
    • https://esprimagroup.com/userfiles/file/gomox.pdf
    • http://pokewaveanaheim.com/uploads/files/18163218581.pdf
    • http://elskup.pl/images/assets/file/57561089935.pdf
    • https://yasacompany.com/upload/files/zapexadaxajubakakepod.pdf
    • http://mlight.cz/archiv/file/41656292453.pdf
    • https://sketchup360.vn/wp-content/plugins/super-forms/uploads/php/files/t8bkq1oqfp7bd8stnjn7v2c0dl/wukusujegefunid.pdf
    • http://xn--2e0b30g3uq7pay7m.com/upload/fckeditor/file/pupopebusagame.pdf
    • http://gearonlaw.net/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/kinilazelakumi.pdf
    • https://www.albispanaderia.com/wp-content/plugins/super-forms/uploads/php/files/bfbdd5bf29690ec510683b828eadafdf/bewadifadofixufula.pdf
    • https://patriot.ch/wp-content/plugins/super-forms/uploads/php/files/984n2sf52h03a8e4oanbv4fvrv/velezerawuzobeki.pdf
    • https://hagepoorter.be/files/files/bililajizatokewebud.pdf
    • http://thingsantiquesla.com/userfiles/files/23961556686.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=codigo+de+colores+de+resistencias+ejercicios+resueltos+pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b9b6.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xB9B6 16792 bytes
font_01_sfnt_off0000d1c8.bin
1744e1ba3c75a70b8798434db49cb956aa904757db0d1e1a9177a58ce2e4e2af
pdf-font-stream PDF embedded font (sfnt) at offset 0xD1C8 16456 bytes
font_02_sfnt_off0000faae.bin
25ab9761095f57e98871a755826d7950c4dc4d6f41d16a727ac80c8a96e0f486
pdf-font-stream PDF embedded font (sfnt) at offset 0xFAAE 11056 bytes