Malicious PDF — malware analysis report

Static analysis result for SHA-256 71876ccbb2ea1e28…

MALICIOUS

PDF

77.1 KB Created: 2021-09-02 13:17:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-29
MD5: 0764bf59e10579b70d22fff1f46fadcf SHA-1: cd031718951bf35df208090841c33013904e7c25 SHA-256: 71876ccbb2ea1e2836f5487543638a5d74d033d54a8c03e75ad97caaea5d201c
156 Risk Score

Malware Insights

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

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains numerous links pointing to compromised WordPress sites and other disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of external URI heuristics and the compromised CMS upload link farm indicate a likely phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://www.viksexteriors.com/wp-content/plugins/formcraft/file-upload/server/content/files/16106ad58f0053---podiboludotowino.pdf In PDF document text
    • http://zulassung4you.de/bilder/file/dajezupovosijividevutusob.pdfIn PDF document text
    • http://schuetzenfest-hemeringen.de/ablage/userfiles/files/97869853081.pdfIn PDF document text
    • https://braviengenharia.com.br/wp-content/plugins/super-forms/uploads/php/files/72rsreh9d52pioijcudbbi0qji/51927724288.pdfIn PDF document text
    • https://certifiedmoversinc.com/wp-content/plugins/super-forms/uploads/php/files/5c5db0a6b49046ba9759965838d0222e/zekiri.pdfIn PDF document text
    • http://bortran.com/upload/image/file/20210518115940.pdfIn PDF document text
    • https://greshamgilessalon.com/wp-content/plugins/super-forms/uploads/php/files/4ddebed70093796ed15d8ef013d0cd8c/mupuzezotozabepuziwo.pdfIn PDF document text
    • http://cleannshieldflorida.com/wp-content/plugins/super-forms/uploads/php/files/97601b6bd31ef10d2ea5270531e381c2/pubuvobab.pdfIn PDF document text
    • http://xn--om2b25zm6igqb.com/ckupload/files/5320311991.pdfIn PDF document text
    • http://geoman.cz/data/file/sakujafafugoxig.pdfIn PDF document text
    • https://valleyrestoration.net/home/apf/public_html/ckfinder/userfiles/files/xunimikoxivavusemufobexap.pdfIn PDF document text
    • https://jamurgoreng.net/contents//files/budilofakamapubijibuz.pdfIn PDF document text
    • http://deurwater.com/wp-content/plugins/formcraft/file-upload/server/content/files/16097c437ec776---nosadeg.pdfIn PDF document text
    • http://runo34.ru/attachments/file/ritajasaluwuna.pdfIn PDF document text
    • https://audit-advisers.com/userfiles/file/pezojafixozaduzimom.pdfIn PDF document text
    • http://iberia-ex.com/images/blog//file/81103554661.pdfIn PDF document text
    • http://topopentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/16110fd3fcc113---matadubukumavinoge.pdfIn PDF document text
    • https://lorenzonimmigrationlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608247f5dad60---ferupi.pdfIn PDF document text
    • http://ahxxzx.com/userfiles/202107/file/38811077076.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/160779e474567b---fudiwanebo.pdfIn PDF document text
    • https://zzwgjx.com/d/files/jedodefurumakinak.pdfIn PDF document text
    • http://www.k-24.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087977894b1a---47057359231.pdfIn PDF document text
    • http://letsbelegal.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/sezixepex.pdfIn PDF document text
    • https://vidolamerica.org/wp-content/plugins/super-forms/uploads/php/files/0a89ad934a2f1f381897e71326b4b612/90289922186.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=alfredo+bosi+cultura+brasileira+temas+e+situa%C3%A7%C3%B5es+pdfPDF 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_off0000c381.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC381 11320 bytes
SHA-256: a8eeef3be5cfbb741be0d4f628ab00afd7125f8be66859ff9683dc8a1f917a6b
font_01_sfnt_off0000dd5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD5D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f56f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF56F 18716 bytes
SHA-256: da290c21a34b2a3a640c196a590225c9d16b04dd500b3c46611e3a7071c42e23