Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5403d080df78f5e…

MALICIOUS

PDF

93.0 KB Created: 2021-09-11 03:51:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: a742f2642c87b0417d937f672cd8e339 SHA-1: 6323d74b6f828b8d7cb12b7e47260b5fc97882a4 SHA-256: b5403d080df78f5e0e2d19c60f8b6ecb8eb41503e2a02d051ff7d0e2d72da7e1
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as a malicious PDF by ClamAV and an ML classifier, indicating it is likely a phishing or malware distribution lure. The PDF contains numerous embedded URLs, many pointing to PDF files on various domains, suggesting a link farm designed to obscure the ultimate destination. While no scripts were explicitly extracted, the PDF structure and heuristic firings strongly suggest an attempt to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://lejuriste.ru/files/file/sumefol.pdf In PDF document text
    • http://varadimasszazs.hu/uploads/files/pufinumisubegososesukade.pdfIn PDF document text
    • http://bagpack.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/16133df6019092---89176070900.pdfIn PDF document text
    • http://studiochiodo.eu/userfiles/files/91137524832.pdfIn PDF document text
    • http://etkenkalip.com/files/82324996989.pdfIn PDF document text
    • http://tuderprogettazione.it/userfiles/files/40064406918.pdfIn PDF document text
    • http://reelproductionshd.com/userfiles/file/sufasowo.pdfIn PDF document text
    • https://koltoztetes-szallitas-lomtalanitas.excore.hu/ckfinder/userfiles/files/xikegolelumanibev.pdfIn PDF document text
    • http://tmkb.org.tr/ckfinder/userfiles/files/2149774171.pdfIn PDF document text
    • https://vozilasavozacem.rs/files/mapejefif.pdfIn PDF document text
    • http://studioingegneramato.com/userfiles/files/47550969063.pdfIn PDF document text
    • http://harasim.cz/uploaded/files/burugufikavufovesos.pdfIn PDF document text
    • http://abwrosedale.com/uploads/files/favujedokode.pdfIn PDF document text
    • https://torbay.ru/images/uploads/file/29570064675.pdfIn PDF document text
    • https://jotelek.hu/files/file/7433343201.pdfIn PDF document text
    • https://strategie-forex.com/ckfinder/userfiles/files/limejiron.pdfIn PDF document text
    • https://pilot-nav.com/ckfinder/userfiles/files/64717858605.pdfIn PDF document text
    • https://stallion-international.com/userfiles/file/65423795248.pdfIn PDF document text
    • https://nawaasha.org/userfiles/file/wekazutowimezifukujo.pdfIn PDF document text
    • http://hcbarrett.com/user_area/file/40864297689.pdfIn PDF document text
    • http://dakdekkersindex.nl/images/uploads/54998910285.pdfIn PDF document text
    • http://acunambalaj.com/adenoto/upload/files/sifamojetomeb.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=free+bulk+sms+sending+app+for+androidPDF 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_off000103da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103DA 18760 bytes
SHA-256: 8be948d36b1d89229b9bd4690d5a110322d34e226c6619a95fbdf1701d290fd8
font_01_sfnt_off000134e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x134E4 11052 bytes
SHA-256: 25deda0766e5a117ef4104c53b777acdacd6e8926e27179523bcdd12ecc9cf1c
font_02_sfnt_off00014e25.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14E25 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1