Malicious PDF — malware analysis report

Static analysis result for SHA-256 4225d839cafc3719…

MALICIOUS

PDF

68.7 KB Created: 2021-09-20 03:06:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 178415833fb2d8f5eaff70ad89f313df SHA-1: 6eb1da578f68502d79cefcf9216aceb50f2ced35 SHA-256: 4225d839cafc37197399fa1cfce3bbea39312e524f42814faf38b17acc154508
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by ML and ClamAV as malicious, with heuristics indicating it functions as a link farm. The presence of numerous embedded URLs, many pointing to PDF files on potentially disposable domains, suggests a tactic to manipulate search engine results or distribute further malicious content. While no scripts were explicitly extracted, the PDF structure and URL patterns are indicative of a phishing or SEO spam campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9849

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://s-pack.kr/userfiles/file/20210903112143.pdf In PDF document text
    • http://jewelry-shopping-city.com/uploads/files/202109101146536883.pdfIn PDF document text
    • https://borderpak.com/wp-content/plugins/super-forms/uploads/php/files/cb45671543151f0665532dbc4b2111b2/katadipiwu.pdfIn PDF document text
    • http://girc.ncue.edu.tw/ckfinder/ckfiles/files/10442406719.pdfIn PDF document text
    • https://www.meditech.cz/ckfinder/userfiles/files/nerotitipukodimi.pdfIn PDF document text
    • http://venkateshservices.com/uploads/40393573978.pdfIn PDF document text
    • http://weddingdove.tw/uploads/files/202109060155514581.pdfIn PDF document text
    • https://apgr.eu/UserFiles/file/92162948396.pdfIn PDF document text
    • http://canvangdientu.com/images/file/xeluzawefuzijafovisage.pdfIn PDF document text
    • http://megat.pl/uploaded/fck_files/file/sidagunasexodugol.pdfIn PDF document text
    • http://yameitecl.com/ckfinder/userfiles/files/20210910_124725.pdfIn PDF document text
    • https://www.kindspring.org/inc/ckfinder/userfiles/files/sinajigi.pdfIn PDF document text
    • http://sxhk365.com/uploads/file///dumemer.pdfIn PDF document text
    • http://ipublicity.cz/data/file/55017130197.pdfIn PDF document text
    • https://hv2barrier.com/application/third_party/ckfinder/userfiles/files/xifekamojilu.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/16141e6488254b---62707854845.pdfIn PDF document text
    • https://coffotea.com/uploads/files/202109070133163021.pdfIn PDF document text
    • https://vvpta-irvine.org/userfiles/file/puselus.pdfIn PDF document text
    • http://xn--82cac8d3ajrc0gd0bo4a7nf3qg.com/userfiles/files/sojifomopebipiwemuzo.pdfIn PDF document text
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c18c0436bd---kiluw.pdfIn PDF document text
    • http://studiodabo.eu/userfiles/files/37427638978.pdfIn PDF document text
    • https://nacionalequipamentos.com/ckeditor/uploads/files/28816357283.pdfIn PDF document text
    • https://nvsrolko.org/ckfinder/userfiles/files/19280035853.pdfIn PDF document text
    • http://www.atccs3.it/atccs3/fckeditor/editor/ckfinder/userfiles/files/75738805177.pdfIn PDF document text
    • http://xahscw.com/userfiles/file/dirusokagujijekoribigap.pdfIn PDF document text
    • http://nova-auto.com/upload/tudorav.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=android+10+rom+file+downloadPDF 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_off0000b1d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1D4 10492 bytes
SHA-256: a6fc04d3bd3da6588f08e8511866772491e125833996e4ff88cd7315e9c67b42
font_01_sfnt_off0000c9b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9B4 14144 bytes
SHA-256: a037d254af9e1b1d850c11a63f7a68fea018d552e655a92494aade7a67dc83ef
font_02_sfnt_off0000ed03.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED03 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1