Malicious PDF — malware analysis report

Static analysis result for SHA-256 21fbb4d6f51c6690…

MALICIOUS

PDF

100.2 KB Created: 2021-07-16 01:41:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-16
MD5: 003d75d87805aed480c000f847f4e90e SHA-1: 5837aa2b49aaa5635b9c178af0c9437b4f18de74 SHA-256: 21fbb4d6f51c6690f9cc87f980d4dff2b6bfbd06b15ca1e7a40276aa53122732
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The document functions as a link farm, containing numerous URLs pointing to compromised WordPress sites, likely serving as a distribution point for phishing or malware. The presence of external URIs and link farm heuristics strongly suggests a malicious redirection scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9936

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://laborke.ru/uplcv?utm_term=wuthering+heights+chapter+wise+summary PDF link annotation
    • https://www.gsccn.it/wp-content/plugins/formcraft/file-upload/server/content/files/1607fbff639663---nevesitobalupexuwuf.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab6b499f81b---marefinu.pdfIn PDF document text
    • http://countrysquirefoods.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081359d4ceb1---sarozefetewiwofoxokikuzu.pdfIn PDF document text
    • https://www.shopveriamici.com/wp-content/plugins/super-forms/uploads/php/files/qq29bga9m01t0ov82v4168ql0k/96482822901.pdfIn PDF document text
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/160726a87e5715---zekekidapabo.pdfIn PDF document text
    • https://adm.allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/19e3af65fcfd23b024108add66181a7c/guzerumawinona.pdfIn PDF document text
    • http://sns.hu/_user/file/33213109549.pdfIn PDF document text
    • https://aronabritcan.com/userfiles/file/vumigopisap.pdfIn PDF document text
    • https://www.escon.it/wp-content/plugins/super-forms/uploads/php/files/a0ac898d030f41ccf46666f6fba11d69/migasobujuzenevifu.pdfIn PDF document text
    • http://www.lavalledesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/160756991e4d11---56822835091.pdfIn PDF document text
    • https://aneri12.cz/res/file/lumifawigububujuwonufozot.pdfIn PDF document text
    • http://bagpack.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/160bbbe6fd9ece---43039505090.pdfIn PDF document text
    • https://www.projectorrentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b7629ed7bf4---rugopegaresum.pdfIn PDF document text
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609494cf5c783---xaxoku.pdfIn PDF document text
    • https://www.a2zmedical.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16095fcd353f1c---53622935163.pdfIn PDF document text
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609fc9cfdf7fb---dikirabanupusixus.pdfIn PDF document text
    • http://lukinserv.hu/file/fudutuxuget.pdfIn PDF document text
    • https://alsterparkett.de/wp-content/plugins/super-forms/uploads/php/files/uhfhjpm5pnogbhlb7dg054mlhj/4325987225.pdfIn PDF document text
    • http://millecolori.it/images/file/53831642148.pdfIn PDF document text
    • http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bb008503725---1104329754.pdfIn PDF document text
    • http://vinag7furniture.com/app/webroot/files/editor_upload/files/gexosumikob.pdfIn PDF document text
    • http://gleneaglehoa.org/images/file/jumuje.pdfIn PDF document text
    • http://netinflux.net/userfiles/file/wexije.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_off000124d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x124D3 17440 bytes
SHA-256: 9341254d994dc8fac0887ba7e84082f595785f4286a1d6be35101915e39c8357
font_01_sfnt_off000151f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x151F2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00016a09.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16A09 10948 bytes
SHA-256: 93348933a2bea672ab98be8b71b202546270c73f09b59de3cee557b77c5a73ab

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