Malicious PDF — malware analysis report

Static analysis result for SHA-256 981dfd5ce9f689e2…

MALICIOUS

PDF

77.5 KB Created: 2021-05-28 05:03:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-29
MD5: a6c40c6b5286fa62868549122a80a3b4 SHA-1: 5892f67b829425709f5354ca4591805c3986f816 SHA-256: 981dfd5ce9f689e2bb096a2620834b31458ac477519400cf3ef2b40af4467146
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links pointing to compromised WordPress sites, suggesting a link farm used for phishing or malware distribution. The document body, though partially corrupted, references an audiobook, likely a lure to encourage clicks on the embedded malicious URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 https://stewsites.com/wp-content/plugins/super-forms/uploads/php/files/9d16923cebd23b1df77c96b8421eaac1/56379560053.pdf In PDF document text
    • https://www.horisunmauritius.com/wp-content/plugins/super-forms/uploads/php/files/6af6c81be2a8391cb053bafbdc9b58a5/25341914881.pdfIn PDF document text
    • https://glasschneider.koeln/wp-content/plugins/super-forms/uploads/php/files/f014p5k8feubr3os1n6kv0tcvo/21849334057.pdfIn PDF document text
    • http://churchliferesources.org/wp-content/plugins/formcraft/file-upload/server/content/files/1609eaca451c41---zulubixu.pdfIn PDF document text
    • http://optimus.org.au/wp-content/plugins/formcraft/file-upload/server/content/files/160b03623afec4---89571135561.pdfIn PDF document text
    • https://amalighting.com/wp-content/plugins/super-forms/uploads/php/files/403c11e2b3090fc03b089808d4a457e2/tatoxuwipolokarakoridevi.pdfIn PDF document text
    • https://www.msolartop.cz/wp-content/plugins/formcraft/file-upload/server/content/files/160aa16211290e---juwopexozujule.pdfIn PDF document text
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/c8cf14a30f37a7b394f11cab580d5f64/13117156546.pdfIn PDF document text
    • http://dom-nenilovo.ru/wp-content/plugins/super-forms/uploads/php/files/98fd378ed8694d0263139c1f0b560424/sexutizuravewodijekuzo.pdfIn PDF document text
    • https://www.audioclinica.pt/wp-content/plugins/super-forms/uploads/php/files/ao8qhou7jo95vb27u0e0g9mmu9/94363468478.pdfIn PDF document text
    • http://victorylimo1.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070a129ed232---dufurexe.pdfIn PDF document text
    • http://mgmkt.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16084e3d1153ed---zafan.pdfIn PDF document text
    • http://www.onekaddy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a49f099a7d---36383041116.pdfIn PDF document text
    • http://architects-desk.com/uploadsfile/84513094450.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/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=la+gaviota+y+el+gato+que+le+ense%25C3%25B1o+a+volar+audiolibroPDF link annotation
    • http://kioskcondoweb.wpengine.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078721d52e16---xusokupuwuzewafiwepazu.pdfIn PDF document text
    • 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_off0000ed53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED53 5572 bytes
SHA-256: a8b596d1715f708909ca14ac1c92606a9a6aca8ae8db568a3c13310564411ffe
font_01_sfnt_off00010014.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10014 12032 bytes
SHA-256: 3b11026960c589722f9a4691d8042e7bbdc65ce5d8715a6138796833789eaf8d