Malicious PDF — malware analysis report

Static analysis result for SHA-256 dc548a0febc6259d…

MALICIOUS

PDF

92.5 KB Created: 2021-09-01 00:02:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 833773d84fd488fbb8d7e3c0068208b5 SHA-1: ea5bd07212e2d89cd9a0c2e2dacd55ad91ec2d03 SHA-256: dc548a0febc6259dd59f90ee93f15c7967b3e85b92beb8e7e50a53f6ee434b51
156 Risk Score

Malware Insights

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

The PDF contains numerous links to external websites, many of which are hosted on compromised WordPress installations and utilize Formcraft plugin vulnerabilities for file uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution through these links. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a vehicle for the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9989

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 http://test.uebersetzungen-nesselberger.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606d7ff144c55---debajanav.pdf In PDF document text
    • https://shastriratanchatterjee.com/ckfinder/userfiles/files/nuzubukosesedowaj.pdfIn PDF document text
    • https://mabuksusu.com/contents//files/bavimexulekexuzabubiwu.pdfIn PDF document text
    • http://www.hj-bouwt.be/wp-content/plugins/formcraft/file-upload/server/content/files/1607a2d0aa243b---5350138091.pdfIn PDF document text
    • http://graphicon.hu/wp-content/plugins/formcraft/file-upload/server/content/files/1609048dd85fea---12918803350.pdfIn PDF document text
    • http://gtshotel.it/images/file/80925683249.pdfIn PDF document text
    • http://www.fliesen-brill.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607c81c39bcd8---xokiradik.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/16092250627ea0---golotufemiximupa.pdfIn PDF document text
    • http://acecaalcoy.com/userfiles/file/nidulevuxefotefosekub.pdfIn PDF document text
    • http://xycrusher.com/d/files/dewev.pdfIn PDF document text
    • https://popa.com.br/wp-content/plugins/super-forms/uploads/php/files/d6591b56eb98e4c6f26369e0283b674f/bubipesiku.pdfIn PDF document text
    • https://law.com.sg/wp-content/plugins/super-forms/uploads/php/files/4f7b2ecf9ff178c00580901335bf45c9/26088512178.pdfIn PDF document text
    • https://nceptionsolutions.com/wp-content/plugins/super-forms/uploads/php/files/42c6aa22fcbc5595b67a72d8dd37c22b/bobirenis.pdfIn PDF document text
    • https://machnhaduong.com/images/uploads/files/44474786629.pdfIn PDF document text
    • https://prolocolidodisavio.org/ckfinder/userfiles/files/lelojagu.pdfIn PDF document text
    • http://aaykpn.com/uploads/editor/files/72890376152.pdfIn PDF document text
    • http://sacoorhealth.pt/site/upload/file/zitevebonojix.pdfIn PDF document text
    • http://onishi-kyosendo.jp/archive/repefod.pdfIn PDF document text
    • http://bomtvplus.com/data/board/file/20210609163538.pdfIn PDF document text
    • http://candybeauty.vn/upload/files/41197402621.pdfIn PDF document text
    • https://aletihad-group.com/userfiles/files/ramorojakanuwubufebem.pdfIn PDF document text
    • https://maidintown.co.uk/wp-content/plugins/super-forms/uploads/php/files/582b60369cfcbf064ea5beddf3e448d6/16510705846.pdfIn PDF document text
    • http://test.uebersetzungen-nesselberger.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609f97868e3fd---28858700415.pdfIn PDF document text
    • https://elektrona.cz/files/file/tujafud.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=doing+10+sit+ups+a+dayPDF 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_off00010537.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10537 18060 bytes
SHA-256: fe77ddcffa3f33f93d1e81faf1ff01c1b1caa5f9a231cdb0d1f0d5cd2e7e09c2
font_01_sfnt_off00013352.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13352 10680 bytes
SHA-256: 319a15447027a23ddc218b233f191eb42a6cdb871be8800d67931868abaa987a
font_02_sfnt_off00014bc6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14BC6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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