Malicious PDF — malware analysis report

Static analysis result for SHA-256 71b9424294ac5e45…

MALICIOUS

PDF

85.4 KB Created: 2021-09-03 09:24:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 97acde8c3efa22d7f803182c913e3b11 SHA-1: 1d9dde914e18fcb869ea18b7454c172991d700d0 SHA-256: 71b9424294ac5e45f88633e554527523c59ecd0eba7e94a16acfae541afe04f4
96 Risk Score

Malware Insights

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

The PDF file contains a link farm pointing to numerous other PDF files hosted on compromised websites, as indicated by the 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' heuristics. The ML classifier also flagged this PDF as malicious with high confidence. The primary purpose appears to be SEO manipulation or hosting malicious content via these external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 http://valleypainclinic.org/userfiles/file/muxusokine.pdf In PDF document text
    • http://i-p-p-c.com/ckfinder/userfiles/files/kexow.pdfIn PDF document text
    • http://matchedtubes.de/userfiles/file/42057201073.pdfIn PDF document text
    • https://www.ptlittleflower.org/wp-content/plugins/super-forms/uploads/php/files/pdp86het2is3q3cjvar5mgvpkp/botawilawi.pdfIn PDF document text
    • http://riverla.vn/uploads/userfiles/file/27916302590.pdfIn PDF document text
    • https://bykevin.com/wp-content/plugins/super-forms/uploads/php/files/740cc6863056b15761d2f863af4b6719/raxogefumuw.pdfIn PDF document text
    • http://www.rec39.ru/wp-content/plugins/super-forms/uploads/php/files/639fe6b423e5cae77ba5d79df8ead87f/77987414997.pdfIn PDF document text
    • http://canxetaidientu.com/images/file/95977494148.pdfIn PDF document text
    • https://chocoinmobiliario.com/wp-content/plugins/super-forms/uploads/php/files/9d51ae303f05480fdb44bcbaf6fbdc6a/tokorewazotulezuleg.pdfIn PDF document text
    • https://www.heracles-hotel.eu/wp-content/plugins/super-forms/uploads/php/files/ap8q4e28r0purqe8hbclkj6une/kiwelu.pdfIn PDF document text
    • https://trsbarriersdirect.com/wp-content/plugins/super-forms/uploads/php/files/dkeba5tmtgt012n37ttnntmi8c/98139501911.pdfIn PDF document text
    • http://www.festivalmarrakech.info/wp-content/plugins/formcraft/file-upload/server/content/files/160ce323d510ec---82695044709.pdfIn PDF document text
    • https://skvely-kup.cz/files/file/tatidikekaludukaguwulizoj.pdfIn PDF document text
    • https://bachson.net/upload/file/bunewenezevelimer.pdfIn PDF document text
    • https://hglobaltourb2c.com/FileData/ckfinder/files/20210614_D2E61B505D34AFC7.pdfIn PDF document text
    • http://teaterskolen-efteruddannelsen.dk/ckfinder/userfiles/files/39420129664.pdfIn PDF document text
    • https://coffotea.com/uploads/files/202108141746034553.pdfIn PDF document text
    • https://cedarcreeksauce.com/wp-content/plugins/super-forms/uploads/php/files/b1776aa5d28592f4ce742d32005d71f1/1099099275.pdfIn PDF document text
    • https://dollarplus98.com/images/upload/files/15418151606.pdfIn PDF document text
    • http://0-50.ru/userfiles/file/wefujuzite.pdfIn PDF document text
    • http://www.dilipprabhavalkar.com/images/file/10252001536.pdfIn PDF document text
    • http://akinmedikal.com/uploads/file/supitolujovoxiko.pdfIn PDF document text
    • https://sirikulsteel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160fdb7c00ab80---kanivejevibij.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=marriage+biodata+format+pdf+simplePDF 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_off0000e944.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE944 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010156.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10156 17636 bytes
SHA-256: a9ffd72917316b812a8f9edce6ed462fa83b8ae2d1bd5333df079ccd860c5968
font_02_sfnt_off00012efb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12EFB 10868 bytes
SHA-256: d67bf99e970852b0afb67790c6284a46138ad7610f84d5849fd5fe1ff387e596