Malicious PDF — malware analysis report

Static analysis result for SHA-256 855af64c7615cd2b…

MALICIOUS

PDF

83.5 KB Created: 2021-09-18 13:25:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 1b0dc3054b5b48d293430bb53fd5ad0a SHA-1: 835bfa4870b47a81b70cecd6213539e353c6f6e8 SHA-256: 855af64c7615cd2bb2aebdac673f59ff86a4623f56689042d6b5798f575ae105
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs pointing to various domains, many of which appear to be compromised or disposable hosting. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a link farm structure, suggesting the PDF's primary purpose is to redirect users to these external sites. The presence of 'wkhtmltopdf' in the metadata suggests it may have been generated by a tool that could be used for malicious purposes.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://ketchas.ru/uplcv?utm_term=restore+images+android PDF link annotation
    • https://cooperadora.grupocreartel.com/documentos/archivos/savezogusugujujig.pdfIn PDF document text
    • http://u15.ch/ckfinder/userfiles/files/jopakesidabisiratotejib.pdfIn PDF document text
    • http://zhongyuemedia.com/filespath/files/20210917095546.pdfIn PDF document text
    • http://wohntraumgmbh.at/32121016366.pdfIn PDF document text
    • https://masterok-kovka.ru/wp-content/plugins/super-forms/uploads/php/files/a689962eb8a63396f21fd680020372e2/28194434905.pdfIn PDF document text
    • http://bumsnab.ru/uploads/files/94352148865.pdfIn PDF document text
    • https://swapnauraan.com/ckfinder/userfiles/files/23840338726.pdfIn PDF document text
    • http://rqconsultores.com/userfiles/file/refusuxebimunufojeda.pdfIn PDF document text
    • http://istanbulballoons.com/ckfinder/userfiles/files/56914870657.pdfIn PDF document text
    • http://www.rolstoellift.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b16d476fa0---76010198121.pdfIn PDF document text
    • https://careerroots.net/ckfinder/userfiles/files/27435926359.pdfIn PDF document text
    • http://terapie-psi.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16140721f1341a---40604541971.pdfIn PDF document text
    • https://tuabogadoangel.com/wp-content/plugins/super-forms/uploads/php/files/128698fd46ede4914b1b23d221fe3e3e/45502632737.pdfIn PDF document text
    • http://landroverbh.com/ckfinder/userfiles/files/24467375109.pdfIn PDF document text
    • https://advantagelic.com/singhania/downloads/file/toxozoniserepon.pdfIn PDF document text
    • http://ducnhua.com/upload/files/5967061635.pdfIn PDF document text
    • https://shreenatharcade.com/userfiles/file/58973471167.pdfIn PDF document text
    • https://pointwebhost.com/calisma2/files/uploads/32943187803.pdfIn PDF document text
    • https://skywaynepal.com/userfiles/file/mojupegarosobuxipagopowa.pdfIn PDF document text
    • https://ailani.org/wp-content/plugins/super-forms/uploads/php/files/5565c30f37b6dde9e45d48e0d9d0a3ce/90666758021.pdfIn PDF document text
    • http://saxonrt.hu/img/userfiles/files/86665703760.pdfIn PDF document text
    • https://ddc-touggourt.dz/ar/files/21657081679.pdfIn PDF document text
    • http://klwas.org/userfiles/images/file/pugiloliz.pdfIn PDF document text
    • http://sigmabhp.pl/userfiles/file/35912407253.pdfIn PDF document text
    • https://longislandinvestmentadvisors.com/nini/userfiles/file/jevaki.pdfIn PDF document text
    • http://canadianrockies.info/files/file/tulilasonixufaweg.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://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_off0000df2c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF2C 18804 bytes
SHA-256: 2f5663d254ce54bc6b5af421ea89495fd8cb83fe6177b778efc2852185b482b6
font_01_sfnt_off0001101b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1101B 10592 bytes
SHA-256: e4d46c7f7f2b108fc96bd86af8477a73c3c74ba38ab2d03b139e42ff2e5e6207
font_02_sfnt_off00012810.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12810 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1