Malicious PDF — malware analysis report

Static analysis result for SHA-256 dcb942ef03fcc71b…

MALICIOUS

PDF

77.5 KB Created: 2021-09-19 21:14:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 686520268bd759f53501e760f2ca6985 SHA-1: 12c5fac1d81880f82087d2bc22b6af99ae1f02a0 SHA-256: dcb942ef03fcc71b6e1911e08febc8c6075c02d29ef8bf9c741f86bf51bf9701
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous embedded URLs pointing to various domains, many of which are hosted on compromised or disposable infrastructure. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically highlights this behavior, suggesting an attempt to lure users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9943

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://cylinder96.ru/admin/ckfinder/userfiles/files/81114957551.pdf In PDF document text
    • http://donahoelawfirm.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/devafatoruj.pdfIn PDF document text
    • http://renknh.com/ckupload/files/lubofudabivesux.pdfIn PDF document text
    • http://sujitonweb.com/userfiles/files/82555447345.pdfIn PDF document text
    • https://sanipro.ma/app/webroot/uploaderfiles/pasafuzolufepaseravota.pdfIn PDF document text
    • http://odra.cycling-recycling.eu/imgturysta/files/lofot.pdfIn PDF document text
    • https://open-call.fr/uploaded/files/74348048607.pdfIn PDF document text
    • http://ninda.vn/userfiles/files/48749094696.pdfIn PDF document text
    • http://nuyewpilot.academy/wp-content/plugins/super-forms/uploads/php/files/fe5532d22130b466efbe77560b829329/zivadeziwujomaku.pdfIn PDF document text
    • https://shreenathtechnologies.com/userfiles/file/fijegoleza.pdfIn PDF document text
    • http://artikos.pl/userfiles/file/pezabej.pdfIn PDF document text
    • http://www.samuitns.com/image/upload/File/88596162717.pdfIn PDF document text
    • http://www.korayozelguvenlik.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134338c9855f---titutubewujodetibo.pdfIn PDF document text
    • https://spbmworld.com/anaeter_capital/siteadmin/userfiles/files/60266462606.pdfIn PDF document text
    • http://rgn2u.com/userfiles/files/newidoxuvakuxamozu.pdfIn PDF document text
    • https://epiphanych.com/images/file/tutawinag.pdfIn PDF document text
    • https://ryokanclub.com/FileData/ckfinder/files/20210909_40E174DA6724761C.pdfIn PDF document text
    • https://cbolean.com/wp-content/plugins/super-forms/uploads/php/files/186779f7c4ae64681678847b3779eda7/62739082107.pdfIn PDF document text
    • http://special-pharma.com/upload/files/19142624320.pdfIn PDF document text
    • https://naves.cz/res/file/dagujidokipiduj.pdfIn PDF document text
    • http://honderhotel.com/UploadFiles/FCKeditor/20210915172929.pdfIn PDF document text
    • http://armanetti.com/images/82353369868.pdfIn PDF document text
    • http://profstil.az/userfiles/file/68941370602.pdfIn PDF document text
    • http://portalpr-b2b.es/img/user//file/_0039679001630592252.pdfIn PDF document text
    • http://nikolalepojevic5.com/multimedia/file/75522686807.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=how+to+build+android+app+in+react+nativePDF 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_off0000c99e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC99E 10724 bytes
SHA-256: a69747ac22404ec208e6e82f378acf152645ed9150b4da61d57e9b4529cb16be
font_01_sfnt_off0000e21c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE21C 17708 bytes
SHA-256: 8b4db09986ecd43fe51d6f2e46778de91eeb2678c776c42b1beb4d459d2e864f
font_02_sfnt_off00011039.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11039 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1