Malicious PDF — malware analysis report

Static analysis result for SHA-256 1711d94259078d13…

MALICIOUS

PDF

89.8 KB Created: 2021-07-30 10:00:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-15
MD5: 1235de37cc4577dc6477c3c96c6597ad SHA-1: bd205d06df2f09176f67263ee4aaf4846a044c4d SHA-256: 1711d94259078d1332184510d5fdb8289cae0e0bacff0868b3d63a2fc7ad2e76
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it functions as a link farm. The embedded URLs predominantly point to compromised WordPress sites, suggesting an attempt to lure users to malicious content or phishing pages. The document body is heavily obfuscated and contains metadata indicating it was generated by wkhtmltopdf, a tool often used to create PDFs from web content, further supporting the link farm hypothesis.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9932

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://chcial.ru/uplcv?utm_term=spanish+verb+tenses+chart+pdf PDF link annotation
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160c19e1fcd998---34418123169.pdfIn PDF document text
    • http://classicalgardenornaments.com/uplds/file/42836879519.pdfIn PDF document text
    • https://regeneracion-capilar.com/wp-content/plugins/super-forms/uploads/php/files/2d0314e68199c2d284fcdc1d4232b6c4/63851392482.pdfIn PDF document text
    • http://counterreaction.net/wp-content/plugins/formcraft/file-upload/server/content/files/160875aef0636d---mexefozarosoparadew.pdfIn PDF document text
    • http://www.skupp.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160f74f95da080---pufetijorigusoror.pdfIn PDF document text
    • https://cuisinescartier.ca/upload/editor/file/sofonodevodilisix.pdfIn PDF document text
    • https://jbdclothiers.net/emailer/userfiles/file/xetenowuzunasezexugati.pdfIn PDF document text
    • http://yepuco.com/uploads/files/fubol.pdfIn PDF document text
    • https://fiambreszav.com/wp-content/plugins/super-forms/uploads/php/files/a54fd9010b749da661d619c41a5875ce/sebowofomomeket.pdfIn PDF document text
    • http://pincailight.com/zk/UploadFile/file/2021062215474873499.pdfIn PDF document text
    • http://inbond-cn.com/userfiles/file/witiledebugilefo.pdfIn PDF document text
    • https://keluargamimpi.com/contents//files/73609207656.pdfIn PDF document text
    • https://thealloywheelcentre.co.uk/wp-content/plugins/super-forms/uploads/php/files/1df9755af3391cf0c4b8b8159adbbb71/xapuvalumeligi.pdfIn PDF document text
    • http://noxsun.com/jingkelun/userfiles/files/20210620222601.pdfIn PDF document text
    • http://bpabv.nl/uploadfiles/file/pujul.pdfIn PDF document text
    • http://synergytaekwondo.com/click2buy_newp/userfiles/file/93633049012.pdfIn PDF document text
    • https://tl-systems.hu/files/files/xanadixojosavadakufeze.pdfIn PDF document text
    • https://vetamblj.si/ckfinder/userfiles/files/tewuderoxiguzekupeboz.pdfIn PDF document text
    • http://sjar-tech.com/uploadfile/file///2021052504095545.pdfIn PDF document text
    • https://g-ortho.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a1678269b2a---46451615315.pdfIn PDF document text
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f0f500fa81---29621206538.pdfIn PDF document text
    • http://msslink.ru/userfiles/files/xuluvuwopex.pdfIn PDF document text
    • http://jandebruijn.com/uploadimages/files/47985191476.pdfIn PDF document text
    • http://cn-junsheng.com/upload/file///2021728195260569.pdfIn PDF document text
    • http://qianxish.com/ckfind_image/files/torinez.pdfIn PDF document text
    • https://rhythmcprandfirstaid.com/wp-content/plugins/super-forms/uploads/php/files/3b0a6ac01252c90c6f124f0263733c9a/89719702648.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_off0000fbb3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBB3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000113c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x113C5 17240 bytes
SHA-256: fbbea7b93d579fa1b466b5f6531af9ba0de6f31603dd470f788a9cc0d374bcd5
font_02_sfnt_off00013fe1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13FE1 10832 bytes
SHA-256: 1bb9521e74efd80dad2217886735abd5355fa5e0768d767b8f76fff1776642f1

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