Malicious PDF — malware analysis report

Static analysis result for SHA-256 c16bd350584f5312…

MALICIOUS

PDF

76.7 KB Created: 2021-06-19 17:44:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-14
MD5: 88fa4aeeebde2c3d58097dfb733db6c1 SHA-1: 3776c85ba2447368bde9bef2f990b27c113447f0 SHA-256: c16bd350584f5312efca290899a27c74d13771823d8c994cc081c2292ef449c4
156 Risk Score

Malware Insights

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

The PDF contains multiple embedded URLs, with several heuristics indicating it functions as a link farm, potentially pointing to compromised websites or phishing lures. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://fresh-cherries.com/ckfinder/userfiles/files/sidixowu.pdf In PDF document text
    • https://zlato-eu.cz/upload/files/gofevakowu.pdfIn PDF document text
    • https://www.denisonlandscaping.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c54e6bd5b83---67172016821.pdfIn PDF document text
    • https://lightspec.com/wp-content/plugins/super-forms/uploads/php/files/9e33e35451b6b4aa6de2ac2f75da6269/59312003988.pdfIn PDF document text
    • http://nsdadventist.org/FCKData/file/komubi.pdfIn PDF document text
    • http://payassistinc.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607435e07b4e7---7439729875.pdfIn PDF document text
    • http://keramann.ru/uploads/files/59319146687.pdfIn PDF document text
    • https://unitedcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608826184e547---80814968090.pdfIn PDF document text
    • http://www.gainerwindows.ca/wp-content/plugins/super-forms/uploads/php/files/ba0ubgapem8eh15j4mlcpbebj3/wadeviximakopobep.pdfIn PDF document text
    • http://www.rolstoellift.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e36ba78431---fajizuzubarilowelemibela.pdfIn PDF document text
    • http://www.thebetterinsurance.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b622f183bb5---21967649306.pdfIn PDF document text
    • http://asokmontridental.com/userfiles/file/niladefemo.pdfIn PDF document text
    • http://smartcookieacademy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090b2595e1a0---19536257382.pdfIn PDF document text
    • https://sportli.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/16080fd8b98c10---katuneza.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/fs8cgb18m1f9t24gahefodrtg0/52459307523.pdfIn PDF document text
    • http://www.sbawerribee.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607fb0283b978---xulunonivipi.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=move+reminder+sun+and+moonPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ed07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED07 5004 bytes
SHA-256: f42e400e5f2f8621daa732cd8ca670bce536f3eb2511fa11e48835a8904ecfef
font_01_sfnt_off0000fe01.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE01 11804 bytes
SHA-256: 7a9b5bd2df3ff98f7d330ebd47e3ea54200be3e10772e81ec87031fa4dd75015