Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b81b5e4cdb609a0…

MALICIOUS

PDF

93.9 KB Created: 2021-07-06 03:56:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 2d9f34cb6794a05fa2fc8afa68ef80c8 SHA-1: 9e8e462f74a21781c801c55b6a69bf8dd5685994 SHA-256: 4b81b5e4cdb609a0b58112dec956dc92bbbc94b12d3b506e973b82d8c893083a
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal numerous external URIs pointing to compromised WordPress installations and disposable hosting, suggesting a phishing or malware distribution campaign. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, but the presence of numerous links indicates a link farm designed to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9935

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
  • Clickable URI points to raw IP address medium PDF_URI_IP_LITERAL
    PDF contains a clickable HTTP(S) action whose host is a literal IPv4 address. Legitimate documents normally link to named domains; raw-IP destinations are common in disposable phishing and malware-delivery infrastructure.
  • 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://crysiq.ru/uplcv?utm_term=parchment+like+skin PDF link annotation
    • http://104.156.58.56/~web2inbox/wp-content/plugins/formcraft/file-upload/server/content/files/160718ddbcd0bd---vuzag.pdfPDF link annotation
    • http://willtorock.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608bb522b0d38---voligoparizet.pdfIn PDF document text
    • http://jonkmp.nl/img/cms/file/23380744518.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b46e6e5c7d0---bijizew.pdfIn PDF document text
    • https://pet-fashion.ro/mm/file/94428542906.pdfIn PDF document text
    • http://www.dramayaramendes.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606ffac4ee3ff---13926501442.pdfIn PDF document text
    • http://erbilsunhotel.com/wp-content/plugins/super-forms/uploads/php/files/sog2u0s06bj8cq22tv4lrae1j7/degumuwewizix.pdfIn PDF document text
    • http://gasthaus-steinkirchen.de/img/editor/file/96854112775.pdfIn PDF document text
    • https://www.enviedecrire.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606defd2aaaec---14431486972.pdfIn PDF document text
    • https://cashofferoregon.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b3f491c91c1---fifumulu.pdfIn PDF document text
    • https://fobiy.net/wp-content/plugins/super-forms/uploads/php/files/5e777cf3c856702d826888c1c2cf97a0/64073736138.pdfIn PDF document text
    • https://www.darrellstuckey.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bba9ea31a7d---89884201165.pdfIn PDF document text
    • https://www.ideakliniksisli.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b4593205704---856089281.pdfIn PDF document text
    • http://apexnepaltravel.com/userfiles/file/pukutitobobo.pdfIn PDF document text
    • https://sygimportaciones.com/wp-content/plugins/super-forms/uploads/php/files/6ap3900694r28buio1ths9lll0/wojowobipazede.pdfIn PDF document text
    • http://www.gametimecatering.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087c40fb89ef---76770562011.pdfIn PDF document text
    • https://lea-inc.com/wp-content/plugins/super-forms/uploads/php/files/4dc20259c73656612c5d0616550a4c43/futodarakovalimadiwusok.pdfIn PDF document text
    • http://www.thunderesp.com/ckfinder/ckfinder.htmlfiles/vamune.pdfIn PDF document text
    • http://uniondeautoescuelas.com/wp-content/plugins/formcraft/file-upload/server/content/files/160850c9ebf287---babatukumawadaz.pdfIn PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/k0d7so6s0a188essjiapd94t16/20157725122.pdfIn PDF document text
    • http://lifestyleufa.ru/wp-content/plugins/super-forms/uploads/php/files/a005afcc552a0fc4b434af1bc59e63e3/69003786625.pdfIn PDF document text
    • http://casaatlantida.com/userfiles/file///84934707708.pdfIn PDF document text
    • https://www.burit.net/wp-content/plugins/formcraft/file-upload/server/content/files/160b7fdd886348---muzinalefikokiguxunojogu.pdfIn PDF document text
    • http://agataklimowska.pl/userfiles/file/21262362110.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_off00010d8d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D8D 17656 bytes
SHA-256: 0fd93fbc0ecba6d20a07dd36c6023954f1ecf2662f67ea53317d7b8bfd377dda
font_01_sfnt_off00013b26.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13B26 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001533d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1533D 10468 bytes
SHA-256: 331fe72bc344f3517dbc3d48a6c200123a020a80c832be447378e3d2f3e89f4d

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