Malicious PDF — malware analysis report

Static analysis result for SHA-256 16cb1c4891ebf5d0…

MALICIOUS

PDF

86.5 KB Created: 2021-09-07 20:00:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-16
MD5: a06bf5501afb028f4ba7027cb68a1cfa SHA-1: a27d865ac417f11899595a59d49747b6ec34065b SHA-256: 16cb1c4891ebf5d05887c3859ce4768706e7b2d19a03e7eee216e13999da2a8f
96 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous websites, with several URLs hosted on compromised CMS platforms. The ML classifier strongly indicated maliciousness. While no scripts were extracted, the structure and URL distribution suggest an attempt to lure users to potentially malicious or SEO-manipulated content, possibly as a phishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 5

  • 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://mdsalon.ru/img/lib/file/podixip.pdf In PDF document text
    • http://codienlanhminhquang.com/upload/files/15913169246.pdfIn PDF document text
    • http://shqinze.net/admin/upimg/file///govapadopola.pdfIn PDF document text
    • https://cuisinescartier.ca/upload/editor/file/josasuxite.pdfIn PDF document text
    • http://trainternational.in/wp-content/plugins/formcraft/file-upload/server/content/files/160b389c771081---kejopugi.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d86db52bfd---nufirubenokelifofi.pdfIn PDF document text
    • http://ssteelelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/91494835026.pdfIn PDF document text
    • https://vuaship.com/wp-content/plugins/super-forms/uploads/php/files/2abqvc5m1iqc3pone8niu6ud6f/musisarejakikibimelupis.pdfIn PDF document text
    • http://bibliotekaludwin.pl/img/upload/files/60437269771.pdfIn PDF document text
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a63e9889d68---52711204518.pdfIn PDF document text
    • http://jerseybankruptcylaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/segeduripidiwuligo.pdfIn PDF document text
    • https://izharfoster.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cae78f20e2d---92470898680.pdfIn PDF document text
    • https://immobiliaresancarlotrieste.it/file/374667669.pdfIn PDF document text
    • https://shopexpert.com/app/webroot/files/userfiles/files/xogiligipewilez.pdfIn PDF document text
    • https://ukmriptek.org/codeIgniter-hmvc/userfiles/files/woraxixatukaxebinazitu.pdfIn PDF document text
    • https://balarampurblock.in/ckfinder/userfiles/files/rorufutewup.pdfIn PDF document text
    • http://odpadykj.cz/UserFiles/File/bojeneguvogisuvika.pdfIn PDF document text
    • http://phongkhamthienhoa.org/images/files/57103375964.pdfIn PDF document text
    • https://performanceltg.com/wp-content/plugins/super-forms/uploads/php/files/36b29ce54bcdb75c1d9434e91f3a382f/71342462249.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d6cafe9866---nopunafobiwezikesir.pdfIn PDF document text
    • http://pmmagic.vn/userfiles/file/40514396088.pdfIn PDF document text
    • https://xn--mietkndigungsrecht-best-gpc.de/userfiles/file/78682856626.pdfIn PDF document text
    • https://www.rath-catering.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b9fb1437d1a---50331804499.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=basic+electronics+engineering+books+pdf+free+downloadPDF link annotation
    • https://bxthirteen.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/9e18e9d295497a4d2ca6f1594047ad3d/valovo.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_off0000e85f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE85F 11168 bytes
SHA-256: 9ef535b9a9767591d153057e27dd574081a0f35be4951cff2fc50f4109e1a63d
font_01_sfnt_off00010247.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10247 19644 bytes
SHA-256: 926b7d69e5bec84550cabb2346eb7943df72a79cf1c834385c9e5e5c44df99ee
font_02_sfnt_off0001338a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1338A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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