Malicious PDF — malware analysis report

Static analysis result for SHA-256 40dd57e761824bd7…

MALICIOUS

PDF

74.5 KB Created: 2021-05-28 13:21:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-23
MD5: e53e6ecc836dedb0e9bfe98a2a56666b SHA-1: d631ba4ac83dd37de08924e0d0c2ebf0a48ec89a SHA-256: 40dd57e761824bd7b6360a609a0ab2c696d01ca6ae3170bb65afc5bf5695469e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file contains numerous links pointing to compromised WordPress sites and disposable hosting domains, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly suggest malicious intent, with the PDF_SEO_DISPOSABLE_LINK_FARM heuristic confirming the nature of the links. No scripts were extracted, but the structure and URL findings are sufficient to assess the attack pattern.

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 http://anhuizhkj.com/upload_fck/file/2021-4-30/20210430141032880075.pdf In PDF document text
    • https://www.isnb.co.uk/wp-content/plugins/super-forms/uploads/php/files/07fb27a0c78bf343156b5f018f8199c8/95943068068.pdfIn PDF document text
    • https://www.davidcosz.de/wp-content/plugins/super-forms/uploads/php/files/jaucc6c3eskpbq90pradbtun9g/zikarolawosimasonerivi.pdfIn PDF document text
    • https://iescolumbus.org/wp-content/plugins/super-forms/uploads/php/files/578f5a0638efc24b5570412cfda2c5e5/39327410518.pdfIn PDF document text
    • http://pvsystexperts.com/wp-content/plugins/super-forms/uploads/php/files/e3hai58up5r3b2f20pniglphi1/66088558214.pdfIn PDF document text
    • http://www.sunaryem.com.tr/wp-content/plugins/super-forms/uploads/php/files/21jmv8gnt92jvggl899qq03l06/dulaxiwaguponujaziju.pdfIn PDF document text
    • https://bodegoncriollo.com/userfiles/file/96064084671.pdfIn PDF document text
    • https://www.stamfordtaxis.com/wp-content/plugins/super-forms/uploads/php/files/2vs7n5386im7pphtn2gt04kfkt/zowatitiwavumexajomev.pdfIn PDF document text
    • http://www.onegelha.com/wp-content/plugins/super-forms/uploads/php/files/c6389a050538b4516cc1a27a4d4c7838/85465252724.pdfIn PDF document text
    • https://medtek.vn/storage/file/mutesimanudepum.pdfIn PDF document text
    • https://www.ccps.mx/wp-content/plugins/super-forms/uploads/php/files/2bbd840e028eebdb5d769f3efbe690a2/98001431941.pdfIn PDF document text
    • http://friluftsgruppen.se/wp-content/plugins/formcraft/file-upload/server/content/files/16085ae240b558---74194442657.pdfIn PDF document text
    • http://evabody.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1606ee9094659d---57552309047.pdfIn PDF document text
    • http://modelkyujin.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609eefff4c06a---91238758826.pdfIn PDF document text
    • http://atut-biuro.com/uploaded/file/45274854204.pdfIn PDF document text
    • https://aihr-iadh.org/uploads/FCK_files/file/36032508575.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=the+things+they+carried+chapter+20+questions+and+answersPDF 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d859.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD859 5728 bytes
SHA-256: 76a52b8f2364943449b74a412512c3608eed946fafd453e14acc97542af2d1ba
font_01_sfnt_off0000ebdd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBDD 10108 bytes
SHA-256: d72c3c11bb0a1fca261ab43c7ac164f17cd4b08f136a56a65790d898a8c3cf28
font_02_sfnt_off00010e87.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E87 4324 bytes
SHA-256: ff5f0ef16caf3e97cd1984b3a03ea88e11eab8cf63d2ee006085a4b9995833f3