Malicious PDF — malware analysis report

Static analysis result for SHA-256 51d74b596c49f957…

MALICIOUS

PDF

83.4 KB Created: 2021-09-17 05:45:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 40b6641906e708aaf2bd30db187bcbd4 SHA-1: 29fc17ad981aad99390721b5b03e465b640361a3 SHA-256: 51d74b596c49f95729ed8fef5ffd86c20fa92ef1992332725a8726ae41ab41ff
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Numerous URLs were extracted, many pointing to disposable hosting or compromised WordPress sites, indicating a link farm designed to redirect users to malicious content. The presence of multiple external URIs and link farm heuristics strongly suggests a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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://laborke.ru/uplcv?utm_term=how+to+free+up+phone+memory+space+on+android PDF link annotation
    • http://v-lukomorie.com/uploader/files/78782071293.pdfIn PDF document text
    • https://indikino.com/ckfinder/userfiles/files/zufolijerojifur.pdfIn PDF document text
    • https://kfmaccounting.com/webroot/img/content/files/boravoku.pdfIn PDF document text
    • http://france-ex.com/images/blog/file/33362148955.pdfIn PDF document text
    • http://thietbimaugiao.vn/Images_upload/files/70017093403.pdfIn PDF document text
    • http://2girlstrippin.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613281fcdbc96---13235234581.pdfIn PDF document text
    • https://comobrew.com/newsite/images/user_uploads/file/84204653008.pdfIn PDF document text
    • https://icbacademy.com/upload/files/47007797138.pdfIn PDF document text
    • https://fmpride.com/wp-content/plugins/super-forms/uploads/php/files/40de7cec8f8fe45e1694c32b7b0a2347/2505819477.pdfIn PDF document text
    • https://seo-methodes.com/userfiles/file/31316184441.pdfIn PDF document text
    • http://sobinco.cz/ckfinder/userfiles/files/31608003027.pdfIn PDF document text
    • http://mrcubezpieczenia.pl/app/webroot/media/files/kulimekolibowopujumako.pdfIn PDF document text
    • http://idrogastermoclima.it/Utentifile/FCKPage/file/mafunofiposetiro.pdfIn PDF document text
    • http://bilmatbasim.com/userfiles/file/5403555707.pdfIn PDF document text
    • http://stefanourso.com/public/userfiles/file/sovedujapifax.pdfIn PDF document text
    • http://friulanapanini.com/images/file/29899965346.pdfIn PDF document text
    • https://databaze-zdarma.cz/userfiles/files/62180285900.pdfIn PDF document text
    • http://ecohouse-lab.de/userfiles/file/68929375591.pdfIn PDF document text
    • https://www.medicalart.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16143ce430c0ae---lozesig.pdfIn PDF document text
    • https://ra7a7p-h3ba7.com/contents/files/dukifalemiz.pdfIn PDF document text
    • http://www.anclupnapoli.it/userfiles/file/72816626540.pdfIn PDF document text
    • https://arrayamed.com/userfiles/file/sirumipunefedavero.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_off0000e0df.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0DF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f8f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8F1 17516 bytes
SHA-256: 2fddd0422f49ac4a6a684c1216999698f72418985391b1095f4d0fdbf748b8e0
font_02_sfnt_off00012694.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12694 11132 bytes
SHA-256: fec06a496358b6b10aebfdc3bc522ec272e4694068b9cb411c2e181a737edabf