Malicious PDF — malware analysis report

Static analysis result for SHA-256 16a51af72dbab58a…

MALICIOUS

PDF

63.0 KB Created: 2021-06-20 03:02:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: 1090084f5e3d280b840b76d3c5e9f32b SHA-1: 050bc3da354b0fb5ba6cc9b6af6b3c363f821a1c SHA-256: 16a51af72dbab58a56dcc416269bf0ee83bf64d5779abc1865d6e55fa83a3e27
156 Risk Score

Malware Insights

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

The PDF file contains multiple heuristics indicating it is a link farm hosted on compromised CMS upload directories, suggesting a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly indicate maliciousness. Although no scripts were directly extracted, the PDF structure and embedded URLs point towards an attempt to redirect users to malicious sites, likely for further exploitation.

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://www.opdrrustukalac.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0843d1fa46---fapebuwoxujidavagudipo.pdf In PDF document text
    • http://studiotecnicoarduini.eu/userfiles/files/nidev.pdfIn PDF document text
    • https://argumentua.com/i/file/sizozitarakuzojafavopelix.pdfIn PDF document text
    • http://queuemanagementsystems.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608446121562c---renafiriwasezun.pdfIn PDF document text
    • https://refundsrefunds.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9f2d1de19f---zamaxifukurelixarisidupus.pdfIn PDF document text
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d09e8eb4c8---6421367162.pdfIn PDF document text
    • https://certifiedmoversinc.com/wp-content/plugins/super-forms/uploads/php/files/cb1082b94a52cc42077de9702d883b78/88878951437.pdfIn PDF document text
    • https://www.saammohaseb.ir/wp-content/plugins/super-forms/uploads/php/files/46d3d80949ddcd1226024d8bc5c4fb1f/kavizekonatixujurunotoju.pdfIn PDF document text
    • https://www.kngroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d5b1d6b950---sinekagaritiveziwo.pdfIn PDF document text
    • https://www.ferienhof-schneider.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a0dac7d3172---lezatukuvitilomodobiliga.pdfIn PDF document text
    • http://101-games.ru/images/uploads/files/nepogivilel.pdfIn PDF document text
    • https://mfdesign.hu/files/file/jexezebezajus.pdfIn PDF document text
    • https://bonafideonline.com.ar/wp-content/plugins/super-forms/uploads/php/files/070285ff463be1dde7677398d549bef9/15395752815.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/1607851bf5dd12---97205578870.pdfIn PDF document text
    • https://engexam.info/wp-content/uploads/2019/07/FCE%20Listening%In 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/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=incident+report+listening+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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b4e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB4E7 5268 bytes
SHA-256: ab45e249fa3ea29a8ca101cc4c201be4305198e286efac9f38fef090dda640da
font_01_sfnt_off0000c6f4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC6F4 13708 bytes
SHA-256: 4d3f84f905ce6ba646b58f804e1dfbc93bd1e1424e23b15615a074570c6c5047