Malicious PDF — malware analysis report

Static analysis result for SHA-256 1c48990c27c7699e…

MALICIOUS

PDF

70.5 KB Created: 2021-09-16 20:11:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 2b13b3a73519a50181d357efecca7ceb SHA-1: d183fa536f1e3bc3f5e5db129934270d62caedae SHA-256: 1c48990c27c7699eb00b8a5a6eeef1faac75b907f5c1250d39b60acde852ee90
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to other PDF files. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically flags this behavior as suspicious. While no scripts were explicitly extracted, the nature of the PDF and its embedded links suggest it is part of a phishing or SEO manipulation scheme, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://magdrywall.com/project-new/christianbook/upload_images/file/50155545789.pdf In PDF document text
    • http://murzilka.biz/images/uploads/file/82562468846.pdfIn PDF document text
    • https://probidjp.com/ckfinder/userfiles/files/20210917_001828.pdfIn PDF document text
    • https://sirikulsteel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612ebd010e9b6---34288173919.pdfIn PDF document text
    • http://dentish.ru/ckfinder/userfiles/files/8097040460.pdfIn PDF document text
    • https://asoriofrio.org/ckfinder/userfiles/files/9383985406.pdfIn PDF document text
    • https://smsenerji.com/resimler/files/jawobok.pdfIn PDF document text
    • https://pastravariaizvoarelebratiei.ro/images/file/44651238046.pdfIn PDF document text
    • http://greenmodels.ru/uploads/files/60607580297.pdfIn PDF document text
    • https://dottoridegregorio.it/public/file/mufozoxinap.pdfIn PDF document text
    • http://www.medical-psychology.gr/wp-content/plugins/formcraft/file-upload/server/content/files/161308d998c0f1---93961611580.pdfIn PDF document text
    • https://babetravelling.com/ckfinder/userfiles2/files/wikoridovuxeb.pdfIn PDF document text
    • https://everestart.com/images/stories/file/31918027074.pdfIn PDF document text
    • http://www.sintsprev-ms.org.br/ckfinder/userfiles/files/30972071011.pdfIn PDF document text
    • http://ancheng-medical.com/uploadfile/files/deverikolijipebugi.pdfIn PDF document text
    • http://pescepiana.eu/userfiles/files/17820549203.pdfIn PDF document text
    • https://taucaotoccatba.vn/images/news/files/joreriwuvefowokesubufa.pdfIn PDF document text
    • https://hoya.hr/UserFiles/file/53400928377.pdfIn PDF document text
    • https://paroles-vives.com/ckfinder/userfiles/files/vodunera.pdfIn PDF document text
    • http://schoonhovensvrouwenkoor.nl/ckfinder/userfiles/files/88192498187.pdfIn PDF document text
    • https://verredistri.fr/xmedia/file/bigegovuribabeges.pdfIn PDF document text
    • https://aluvioneschicamocha.sinecsas.com/ckfinder/userfiles/files/82264517615.pdfIn PDF document text
    • http://rooptex.com/uploads/26638522391.pdfIn PDF document text
    • http://archetipoingegneria.it/userfiles/files/duberexovimurizixira.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=advanced+grammar+in+use+pdf+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_off0000b2d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB2D5 15580 bytes
SHA-256: c738bbef78dc900717f98ff60459526e8d14fe9e8c7880b732eb81097065aa40
font_01_sfnt_off0000da52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA52 11100 bytes
SHA-256: c1088f5524fa08a6c18167a941a99c1546c448224852d634565036a21cadb95b
font_02_sfnt_off0000f40d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF40D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1