Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4f5167873c64bfb…

MALICIOUS

PDF

76.1 KB Created: 2021-09-06 09:24:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 18c42045438af1f23889d033c307969f SHA-1: fcde933745d9ca0bd6472b22789c74945c68b34f SHA-256: b4f5167873c64bfb29bc411279785ec3bfd61d0cabcc0f827fb9a50b0be57834
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to other PDFs hosted on compromised websites. This suggests a multi-stage attack where the initial PDF serves to redirect users to further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://bckbytow.naszbip.pl/img/upload/files/62065944690.pdf In PDF document text
    • https://www.loscam.com/lib_common/ckeditor/ckfinder/userfiles/files/riluxeperewasepetabiv.pdfIn PDF document text
    • https://pasarantogel.com/contents/files/runexixufeveboj.pdfIn PDF document text
    • https://bettenbaehren.de/wp-content/plugins/formcraft/file-upload/server/content/files/160cca03a96f1f---18258608249.pdfIn PDF document text
    • https://www.hintonassociates.com/wp-content/plugins/super-forms/uploads/php/files/2e4efeca74793ee0e22eb4f309f9a2be/8736640347.pdfIn PDF document text
    • http://radio-salsa.com/php/rs/filesupload/file/55423356337.pdfIn PDF document text
    • http://sazjah.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bce0b2876eb---9078481772.pdfIn PDF document text
    • https://progin.ch/ckfinder/userfiles/files/pafejaruwewimomika.pdfIn PDF document text
    • http://ovodatar.hu/userfiles/file/96753136572.pdfIn PDF document text
    • https://www.karenlovelee.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130f7bfa8b72---87172251145.pdfIn PDF document text
    • https://www.reliancecareuk.com/wp-content/plugins/super-forms/uploads/php/files/ed4b4c1d93461eb51826e75b947c8175/23546702124.pdfIn PDF document text
    • http://jatechkj.pl/upload/fck/file/tunowadugemaxe.pdfIn PDF document text
    • https://medgarlci.com/wp-content/plugins/super-forms/uploads/php/files/f303bd72b74d78995763d2872c948996/61574001372.pdfIn PDF document text
    • http://doks-films.com/pcms/content/file/38802762076.pdfIn PDF document text
    • http://www.virtualaid.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1607ce131b6969---lasegav.pdfIn PDF document text
    • http://samsung-service-center.ru/uploads/files/64464515124.pdfIn PDF document text
    • https://www.propertyfilevault.com/wp-content/plugins/super-forms/uploads/php/files/18c5f64c9d1a04ca0f2b793f4e1fd5c7/ruvefod.pdfIn PDF document text
    • https://mamproducciones.es/wp-content/plugins/formcraft/file-upload/server/content/files/1608cb3d99bcac---65920461991.pdfIn PDF document text
    • https://citytrafik.nu/images/file/jubuno.pdfIn PDF document text
    • http://darec.sk/files/files/94974718014.pdfIn PDF document text
    • http://monarchiaerembolt.hu/tmp/muxexexaniget.pdfIn PDF document text
    • https://spaslask.pl/wp-content/plugins/super-forms/uploads/php/files/sfaqn66j10l5vqt1krjalo3l23/niwediratopijejut.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=nfl+schedule+week+16+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_off0000c729.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC729 10516 bytes
SHA-256: afd40c8d2f2ae343e13b1ec19ec9d31ae36cab0e6b5b39c717cd1f4562d30cdc
font_01_sfnt_off0000df54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF54 16956 bytes
SHA-256: 4731a67e3d99c4b2c5daf801662ace76806b76b9f6fbdc74fdd04166250a6c79
font_02_sfnt_off00010b17.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B17 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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