Malicious PDF — malware analysis report

Static analysis result for SHA-256 51ac1b421d11675e…

MALICIOUS

PDF

87.6 KB Created: 2021-07-02 03:24:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: b8b6880be477b932a7a3d53bcccac17e SHA-1: 570cceadae1aa1d8c0d77d47b333f035d9d4d109 SHA-256: 51ac1b421d11675ec8f84b05d3dfd59401b1e76bc581df51491516e2dc702b06
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous embedded URLs pointing to compromised CMS upload storage, suggesting it's used to distribute phishing content or further malware. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' confirms this behavior, indicating the document's primary purpose is to host a large number of links on potentially disposable or compromised domains.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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://zdravi-kromeriz.cz/files/file/73581319159.pdf In PDF document text
    • https://www.mobytec.com.br/mobytec/wp-content/plugins/formcraft/file-upload/server/content/files/1608ebf6329c1f---70262712846.pdfIn PDF document text
    • https://alenakovalchuk.ru/wp-content/plugins/super-forms/uploads/php/files/abc57f475fc551b4e55f629f7d5d6445/51574319666.pdfIn PDF document text
    • https://sikanderajam.com/Robinson/ckfinder/userfiles/files/newibudipojedo.pdfIn PDF document text
    • http://www.nanodrywash.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c94a9af4ca---gesas.pdfIn PDF document text
    • https://www.hed-endo.hr/wp-content/plugins/formcraft/file-upload/server/content/files/1607fb89dc4b5a---mokijiwemawezop.pdfIn PDF document text
    • http://quickfix-poland.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c96e9b00bad---3624642679.pdfIn PDF document text
    • https://www.brightfieldbusinesshub.co.uk/wp-content/plugins/super-forms/uploads/php/files/1jqvleq561o81vovsbfho91n04/95771280737.pdfIn PDF document text
    • https://sgpropertylawyers.com/wp-content/plugins/super-forms/uploads/php/files/cb90a8472060e90b6c13bdd6e00f5e09/11590148463.pdfIn PDF document text
    • https://www.qlsny.com/wp-content/plugins/super-forms/uploads/php/files/e122cd4240e080c5883cd56eb6275ad7/30868280224.pdfIn PDF document text
    • https://zazilha.com.mx/wp-content/plugins/super-forms/uploads/php/files/0deb9c07037dcb7bae4439822a279737/77024860915.pdfIn PDF document text
    • https://zazilha.com.mx/wp-content/plugins/super-forms/uploads/php/files/3f425c193839a7fa7b167869c954c7d4/33777273714.pdfIn PDF document text
    • http://cargo3030.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160bdf4c47de9e---xivobakopeseseta.pdfIn PDF document text
    • https://gotoko.com/cmsv2/upload/files/30962984596.pdfIn PDF document text
    • https://www.ideaklinikkadikoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160703fed7babb---15292660583.pdfIn PDF document text
    • https://www.waterlooarmsnewforest.co.uk/wp-content/plugins/super-forms/uploads/php/files/7806bb233cc2229c0cb906fcbea7098d/92580234298.pdfIn PDF document text
    • http://montaze.org/democms/userfiles/file/luvozitiwibujukoje.pdfIn PDF document text
    • http://webcertain.net/contentupload/fckeditorUploads/organization_/file/85276847201.pdfIn PDF document text
    • https://lifo-sea.com/ckfinder/userfiles/files/42020795571.pdfIn PDF document text
    • http://smartarts.bg/userfiles/file/wuwul.pdfIn PDF document text
    • https://markzone.az/wp-content/plugins/super-forms/uploads/php/files/9ttp15fb1a34o02cgjkotm1l4b/pazazejazewototarefuzan.pdfIn PDF document text
    • http://wsp.pl/userfiles/file/petevirabotutoju.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=notting+hill+carnival+2020PDF 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_off0000f270.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF270 17360 bytes
SHA-256: 816514a3aad4828d35fba4162f0ec87c6e4ce29129ed9ff7d9162f483f0dd82f
font_01_sfnt_off00011fdf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FDF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000137f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x137F6 10496 bytes
SHA-256: dc47405c8ea170e0685d82a69e5fcb3c27e8760dd9b09a23281a235c10944bf3

Open this report in the interactive analyzer, or submit your own file for analysis.