Malicious PDF — malware analysis report

Static analysis result for SHA-256 c28f6d5db2cbe874…

MALICIOUS

PDF

87.1 KB Created: 2021-09-13 19:28:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: ab11108dd1555b427d3995d7e3e19fbd SHA-1: 1813cbd06b8197372e26e43efd1d7c45166e3465 SHA-256: c28f6d5db2cbe87450146d272bbb89bba78fd6fe02f6571c0ce3f3e545bedfb7
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, indicating a high probability of malicious intent. It contains a link farm pointing to compromised WordPress uploads and disposable hosting, suggesting an attempt to redirect users to malicious content. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM heuristics further supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://lex-ter.ru/admin/ckfinder/userfiles/files/53450384878.pdf In PDF document text
    • http://blevy.com/ckfinder/userfiles/files/38334024866.pdfIn PDF document text
    • https://senzedigicraft.com/wp-content/plugins/super-forms/uploads/php/files/24376c2421544e9744fbe0c01fdeeac9/5552464639.pdfIn PDF document text
    • http://noavarservice.com/ckfinder/userfiles/files/98896102424.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d1e2fa1eb9---fasasofabubomumajitezaz.pdfIn PDF document text
    • https://www.sacproblemleri.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d178a1c5d6---88930102846.pdfIn PDF document text
    • http://greenhere.cn/upload/ckimg/files/202109132252404655.pdfIn PDF document text
    • https://priscar.com/documents/files/zibudiboxekazuzizotore.pdfIn PDF document text
    • http://eotp.info/sites/default/files/fck/file/20167012755.pdfIn PDF document text
    • http://dabaizhongxue.com/upload_fck/file/2021-9-5/20210905000412640052.pdfIn PDF document text
    • http://crocepadrekolbe.it/userfiles/files/pupesalelorisaba.pdfIn PDF document text
    • http://taociren.com/upload/file/210908091936228252mcagvawljggt.pdfIn PDF document text
    • http://e3edu.vn/public/ckfinder/core/connector/php/connector.phppublic/uploadsfiles/43959067532.pdfIn PDF document text
    • https://etravelbox.com/scgtest/team-explore/uploads/files/korujofigokomagalan.pdfIn PDF document text
    • https://dutchfansitenetwork.nl/ckfinder/userfiles/files/xamemu.pdfIn PDF document text
    • https://relleno-acidohialuronico.com/wp-content/plugins/super-forms/uploads/php/files/d501d8ac1a4f2efbef82ca8cb1ade251/22651323874.pdfIn PDF document text
    • http://lookupagency.es/wp-content/plugins/formcraft/file-upload/server/content/files/16138dd4cf3eca---rirapagaxaturaso.pdfIn PDF document text
    • http://tekmaker.com/upload/files/6956228425.pdfIn PDF document text
    • http://www.farmaciabergua.com/userfiles/files/29174578192.pdfIn PDF document text
    • https://dampinggame.com/calisma2/files/uploads/59939653526.pdfIn PDF document text
    • http://net-marketing.hu/images/files/pebem.pdfIn PDF document text
    • http://coiffurenais.com/userfiles/file/47981768457.pdfIn PDF document text
    • http://daejonggyoyc.com/userfiles/file/20210908072021.pdfIn PDF document text
    • https://keepingscore.org/userfiles/file/doxenutubodukexeterowo.pdfIn PDF document text
    • http://sirinthepgroup.com/userfiles/file/67689317448.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=unit+conversion+app+for+androidPDF 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://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_off0000ef1c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF1C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010733.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10733 10640 bytes
SHA-256: 1bfec97eaac5a16d80a19aec338f86a786bdd3067ed9a67c8d0ff746a6a914bb
font_02_sfnt_off00011fb7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FB7 18056 bytes
SHA-256: 8751571157032dbe2c22dc42646f8b29f55f084a9dc6e4df50ef2e1bc2500692