Malicious PDF — malware analysis report

Static analysis result for SHA-256 281bdb288c7dd4e4…

MALICIOUS

PDF

105.0 KB Created: 2021-07-01 18:05:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 8a6cf9b95b68e73958a3f842c10be62e SHA-1: e43746c4598f03df078b4b411fe5797c57eef721 SHA-256: 281bdb288c7dd4e47e35f421ccb20f3926c916c76e5bbb5a35f20cca0641ea41
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and a machine learning classifier, with high-severity heuristics indicating it contains random and compromised CMS upload links. These links point to various PDF files hosted on potentially compromised websites, suggesting a phishing or malware distribution campaign. The PDF structure itself is heavily obfuscated, and while no scripts were explicitly extracted, the presence of numerous external links strongly implies an attempt to redirect the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9919

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://caf-ljubljana.si/docs/56994695521.pdf In PDF document text
    • http://www.adanakursmerkezi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ef74e640b9---93209302410.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b64e9c6dc4c---tivabiwudoferevezas.pdfIn PDF document text
    • http://archi1919.com/smlclub-files/file/tidiwi.pdfIn PDF document text
    • https://fjordancv.info/wp-content/plugins/super-forms/uploads/php/files/0f36bef2c08d4853c6c7c26741c6037e/dumonamefeduxefep.pdfIn PDF document text
    • http://doublehappyvstheinfinitesadness.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a4725373340---pozorimavijalarakevinanux.pdfIn PDF document text
    • https://broadstripe.com/wp-content/plugins/super-forms/uploads/php/files/ff857956dac89b86e88358870602b4f2/kajapekosokamedidi.pdfIn PDF document text
    • https://burkina-businessschool.com/business_school/uploads/file/56213632441.pdfIn PDF document text
    • https://kantankacreative.com/wp-content/plugins/super-forms/uploads/php/files/d55c88461415812d61f51592d7a5e858/40120769174.pdfIn PDF document text
    • https://www.digitalsofts.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b329538b179---11836398486.pdfIn PDF document text
    • http://wbbray.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609417026c43a---pigowokana.pdfIn PDF document text
    • http://signexpowholesale.com/project-new/christianbook/upload_images/file/23255542137.pdfIn PDF document text
    • https://trichynext.com/wp-content/plugins/super-forms/uploads/php/files/0d05ef5f6477b6674596d1cdd2ccf17e/gekemefekavufizerere.pdfIn PDF document text
    • http://alarmy-kamery24.pl/userfiles/file/59320154106.pdfIn PDF document text
    • http://www.kinoimaging.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608910a8aeb7a---kemiditatoju.pdfIn PDF document text
    • https://velvetskin.pl/wp-content/plugins/super-forms/uploads/php/files/3ec67bac1707ff78c5a3f4e3f352a0ed/98023139215.pdfIn PDF document text
    • http://anhuishangbiao.com/upload_fck/file/2021-5-23/20210523135308836275.pdfIn PDF document text
    • http://goref.ru/files/file/ropotesafer.pdfIn PDF document text
    • https://lawpropertyconsultants.co.uk/wp-content/plugins/super-forms/uploads/php/files/db1lahi8p9pcqf2pqbnb86jsv4/jilodovanuxum.pdfIn PDF document text
    • https://parisautotravel.com/wp-content/plugins/super-forms/uploads/php/files/0er0e7k7t13kohtt3mm1ja0ek0/nebesazijilawevu.pdfIn PDF document text
    • http://artmetinc.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a85ea3b9010---37456454763.pdfIn PDF document text
    • https://eyetracking.pl/userfiles/file/13561481800.pdfIn PDF document text
    • http://www.morenoroofing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087f57fe22d8---30943870765.pdfIn PDF document text
    • https://journeypeople.cc/wp-content/plugins/super-forms/uploads/php/files/70ee56b4ab7b443aa1bf0fd0a73329e9/55660140121.pdfIn PDF document text
    • https://wulf-sanitaer.de/wp-content/plugins/super-forms/uploads/php/files/tvqatou5baf0dvd031pj8omo6q/rawek.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=laser+capture+microdissection+pdfPDF 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_off00013665.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13665 10792 bytes
SHA-256: 2ae0c02a68b2209773487c129f3fbb07f357dc03412be6616bc4f0a04dde124d
font_01_sfnt_off00014f37.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14F37 17984 bytes
SHA-256: 3d60c03bea2c58770fce9e0d5c606b3976b2d16b24b52fda406231ea734a4807
font_02_sfnt_off00017e61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x17E61 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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