Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5763a1d44c403b3…

MALICIOUS

PDF

81.0 KB Created: 2021-09-08 23:16:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 5410eb2123ccd3263086bc8b83d54a26 SHA-1: 488ecd66fa44c892df56b289d65e810349c2a9cf SHA-256: b5763a1d44c403b3a425342bd0bf6843911c3e5255fd4cc72d0e84be8f692a7c
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs pointing to a mix of compromised CMS uploads and disposable hosting domains, characteristic of a link farm. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for SEO manipulation or to serve phishing content. No scripts were extracted, but the structure and URL distribution suggest a phishing or spamming campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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 https://www.edmcenter.xyz/ckfinder/userfiles/files/10044949663.pdf In PDF document text
    • https://www.sevgiliyevideo.net/wp-content/plugins/formcraft/file-upload/server/content/files/161343ade3c9bf---guvulonopisiwori.pdfIn PDF document text
    • https://grupa-energia.pl/attachments/file/bakijul.pdfIn PDF document text
    • http://inventory-acepipe.com/images/uploads/files/96576292167.pdfIn PDF document text
    • https://udruga-invalida.hr/files/55856007716.pdfIn PDF document text
    • http://globalcenterhotels.com/bot/ckfinder/uf/files/jiwapuxisawunuwa.pdfIn PDF document text
    • https://www.burit.net/wp-content/plugins/formcraft/file-upload/server/content/files/1613263c04669c---15669066620.pdfIn PDF document text
    • http://mis.nrru.ac.th/gradjournal/ckfinder/userfiles/files/jezogagavunula.pdfIn PDF document text
    • https://dacoma.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16138398b1ad57---54066043457.pdfIn PDF document text
    • http://janjoling.com/public/ckfinder/userfiles/files/7748390141.pdfIn PDF document text
    • http://dailitara.lt/bites/uploads/file/dilusavegewotewujorixu.pdfIn PDF document text
    • https://ms2gacor.com/contents/files/vadewifivuwosimojivogez.pdfIn PDF document text
    • https://llibreriaha.com/img/events/file/80064180061.pdfIn PDF document text
    • http://doudou.tw/userfiles/files/83583708070.pdfIn PDF document text
    • http://cbgnfinance.com/userfiles/file/losavezise.pdfIn PDF document text
    • http://rilta.net/userfiles/files/55893616936.pdfIn PDF document text
    • https://happycolaborativo.com/uploads/files/buviliziwibikepavug.pdfIn PDF document text
    • https://path.mn/userfiles/files/58163343088.pdfIn PDF document text
    • http://pitchdecor-construction.com/user_img/files/figeniretulovelimolixowa.pdfIn PDF document text
    • http://www.ctnphrae.com/ckfinder/userfiles/files/duwefokevulaz.pdfIn PDF document text
    • http://geotersrl.it/file/31149508259.pdfIn PDF document text
    • http://matsonconstruction.net/userfiles/file/bawopo.pdfIn PDF document text
    • https://westhygiene.hu/editor_up/gotuzejos.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=good+words+that+start+with+the+letter+iPDF 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_off0000d914.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD914 10368 bytes
SHA-256: 02a64be7e82ea2609102c5df54e2c312d651246f7707df3fb7f23679a0a04ff3
font_01_sfnt_off0000f0b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0B9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000108cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108CB 17748 bytes
SHA-256: cb920f437fbb8b872607286fd616836961cae0c511610c082cde131d1d2e74cc