Malicious PDF — malware analysis report

Static analysis result for SHA-256 55a1028b73d834bb…

MALICIOUS

PDF

77.2 KB Created: 2021-06-10 11:56:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-17
MD5: 4ff64b1ac1938424c4c782db1dd720c5 SHA-1: 1d63a6972516bd07a600fa3009ff46498dc53c04 SHA-256: 55a1028b73d834bbb24339f5035cd5956a8c48b91d2f341d1b9b46c037a2d6a7
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, directing users to multiple external websites, some of which are hosted on compromised WordPress installations and serve PDF files. The presence of external URIs and link farm heuristics suggests an attempt to lure users to malicious content, likely for phishing or further malware delivery.

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://pixomot.ru/uplcv?utm_term=9+month+old+baby+weight+percentile PDF link annotation
    • http://caribsplash.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a62f038801d---70300719622.pdfIn PDF document text
    • https://refour.eu/wp-content/plugins/super-forms/uploads/php/files/65bed5cf605dc29a9f11a8f7c8c69187/3812742833.pdfIn PDF document text
    • http://elonsummerstorage.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f313a6c8c5---32807986149.pdfIn PDF document text
    • http://dossalas.com/wp-content/plugins/super-forms/uploads/php/files/a9c05a6c62fe59c331b8a58a7ae3c09d/76121571689.pdfIn PDF document text
    • https://deniz-sogutma.org/img/userfiles/file/71848439592.pdfIn PDF document text
    • http://profisystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607c73d147e53---kixevisogavoxulusupuwu.pdfIn PDF document text
    • http://clinicacomciencia.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609ad4dbdd0d2---gurivon.pdfIn PDF document text
    • http://www.maoles.com/wp-content/plugins/formcraft/file-upload/server/content/files/16098053ac0fe5---17925095074.pdfIn PDF document text
    • http://grupogmec.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073d9d69c1e1---watan.pdfIn PDF document text
    • http://aaexpansionjoint.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070036286ae7---dezazuvujowerurop.pdfIn PDF document text
    • https://salvatoredivilio.it/userfiles/file/55552630441.pdfIn PDF document text
    • https://thewentworthco.com/wp-content/plugins/super-forms/uploads/php/files/9puqepu6nmv9sp9cclih711on7/fapubegomulozadulijed.pdfIn PDF document text
    • http://www.tsssport.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078d115601da---jikupo.pdfIn PDF document text
    • https://myphi.biz/nbloom/fckuploads/file/51115611929.pdfIn PDF document text
    • http://www.maarsehoveniers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607925132935d---41716712468.pdfIn PDF document text
    • http://www.rebranded.tv/wp-content/plugins/formcraft/file-upload/server/content/files/1609beb3fec3e7---posedataxed.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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_off0000efca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFCA 5704 bytes
SHA-256: f78a675abe136ca15eec3c956039c1b9195020e4ae208fff358c9c166ba53690
font_01_sfnt_off00010315.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10315 10720 bytes
SHA-256: b97facfd684b7799a367602ef5184f43b794802f10b3443cd8f1072cebe37f80