Malicious PDF — malware analysis report

Static analysis result for SHA-256 c7a3baa455c33537…

MALICIOUS

PDF

80.6 KB Created: 2021-09-16 01:18:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 0314a1e1e12d6746f3be09e3d543f850 SHA-1: d8f4181f5ad06e1a71e08d8dd9d20e362093673d SHA-256: c7a3baa455c3353761cbc0d2ac179698b2df732b3a68dfd5b6ab67730629d851
96 Risk Score

Malware Insights

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

The PDF file was flagged by an ML classifier as malicious. It contains numerous embedded URLs that point to various domains, many of which appear to be part of a link farm designed to obscure the ultimate destination. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a non-clustered link farm on disposable hosting, and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' suggests links to compromised WordPress upload storage. These findings strongly suggest the document's purpose is to redirect users to malicious sites, likely for malware distribution or phishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 5

  • 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://pixomot.ru/uplcv?utm_term=essentials+of+medical+microbiology+apurba+sastry+2nd+edition+pdf+download PDF link annotation
    • http://wenfengsi.com/wfs/WebFiles/file///2021091313314565.pdfIn PDF document text
    • https://theelementrama9.com/userfiles/files/sonojiru.pdfIn PDF document text
    • https://mkserwis.pl/userfiles/file/xewomusinavizatugutufipi.pdfIn PDF document text
    • http://www.motionmantra.com/userfiles/files/91476829953.pdfIn PDF document text
    • https://ohcsi.com/ckfinder/userfiles/files/77690606784.pdfIn PDF document text
    • http://parentini.it/userfiles/files/35968680030.pdfIn PDF document text
    • https://relaxbotanika.cz/ckfinder/userfiles/files/36187843432.pdfIn PDF document text
    • https://thebottombillion.org/business_school/uploads/file/2982729490.pdfIn PDF document text
    • http://www.jimenez-casquet.com/wp-content/plugins/formcraft/file-upload/server/content/files/161373df44c46a---80897414385.pdfIn PDF document text
    • http://xn--80ackbssfuieecff0e8c.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/4bl1r5tndkuk2jv4cb9cfjt7d3/mesimawilaxosufef.pdfIn PDF document text
    • https://weilaimachinery.com/userfiles/files/96448720717.pdfIn PDF document text
    • http://busangh.com/attfile/fckimg/file///20210914115317_1054596697.pdfIn PDF document text
    • http://tai-group.com/upload/files/musobivoxesaru.pdfIn PDF document text
    • http://kuwaited.com/cote_dor_import/admin/ckfinder/userfiles/files/85679497985.pdfIn PDF document text
    • http://fskyok.com/uploadfile/files/jidafikovafar.pdfIn PDF document text
    • https://vas-vill.hu/userfiles/file/77497785813.pdfIn PDF document text
    • https://svenjakretschmer.com/ckfinder/userfiles/files/dabobojawuveda.pdfIn PDF document text
    • http://confidenzacsapagy.hu/upload/89949589479.pdfIn PDF document text
    • http://imagespa.mx/wp-content/plugins/formcraft/file-upload/server/content/files/161318df726505---dupasigezezizopa.pdfIn PDF document text
    • http://roycraft.ca/userfiles/file/fajololonitofidinuw.pdfIn PDF document text
    • http://equipociclistaugeraga.com/ciclistas/userfiles/file/tetefekobutipevisokuz.pdfIn PDF document text
    • http://klaaswester.nl/img/file/17279285447.pdfIn PDF document text
    • http://yuhao-tech.com/userfiles/file/nuwenola.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_off0000d4cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4CF 11504 bytes
SHA-256: 96b69773e91447bc7832a3e83d9e787862269d41ce998a9ad642b874f6b58d1f
font_01_sfnt_off0000efba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFBA 17272 bytes
SHA-256: 1801a079e497b1b81717750007c6eca7bac205ed96c6b6262c59a0fbf66e0001
font_02_sfnt_off00011c43.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C43 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1