Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef0b666146a57250…

MALICIOUS

PDF

91.9 KB Created: 2021-08-03 10:13:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 99d84939680437976588c8a8071fc625 SHA-1: 88d34db02cfc1b4012432c0d098837f8e8f0285c SHA-256: ef0b666146a5725010c7d002217882a30603d8b459314b1ab0a375e6bb5158f2
96 Risk Score

Malware Insights

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

This PDF file was identified as malicious by an ML classifier and contains numerous embedded URLs. Several of these URLs point to compromised WordPress sites, suggesting a link farm designed to redirect users to potentially malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user reading but rather as a container for these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

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://ccymgr.com/clients/a/ab/abc9983c1712fd324c9320bcfcf975a8/File/lewelexo.pdf In PDF document text
    • https://reifenscho.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b69d5c09ad9---22594860891.pdfIn PDF document text
    • http://clinicoral.com/img/userfiles/files/3280036365.pdfIn PDF document text
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081a45ef1bd7---11420068776.pdfIn PDF document text
    • http://laclonghotel.vn/upload/files/77549768632.pdfIn PDF document text
    • https://action-roofing.com/wp-content/plugins/super-forms/uploads/php/files/0ed53f9c10f1f3d7c085e64623f5607e/50485829900.pdfIn PDF document text
    • http://madonnina.info/userfiles/files/8728910638.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160af8e7734db8---56719359754.pdfIn PDF document text
    • http://www.reroofingbrisbaneqld.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1608d5b628a03c---26735832537.pdfIn PDF document text
    • https://dtcprojects.com.au/wp-content/plugins/super-forms/uploads/php/files/aevk7l9hsinqvaaouqncgt17s4/duwufarugenokudenek.pdfIn PDF document text
    • https://psfund.org/public/uploads/files/cms_files/mapobefif.pdfIn PDF document text
    • https://trade.inter-ural.ru/ckfinder/userfiles/files/kapiwe.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e4073d8298---fewewotinutelizuzolilov.pdfIn PDF document text
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c093668c736---faxel.pdfIn PDF document text
    • http://cnzgks.com/userfiles/file///babatumejodatopife.pdfIn PDF document text
    • http://mijneigenlift.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608da8699a318---39959089797.pdfIn PDF document text
    • https://www.heracles-hotel.eu/wp-content/plugins/super-forms/uploads/php/files/i29uhu4lu9hok1mdeocr7t0o9o/xonaxebuxijapuxawofuji.pdfIn PDF document text
    • http://stroi-sistema.ru/img/wesagigupupepoxonal.pdfIn PDF document text
    • http://uat.ideadunes.com/projects/ideadunes-portfolio-site/wp-content/plugins/formcraft/file-upload/server/content/files/1607efbfe6e116---1701191734.pdfIn PDF document text
    • https://suemsas.com/wp-content/plugins/super-forms/uploads/php/files/j24f8e96ko4c7reh912mfv53f7/tiparipakajufawusezi.pdfIn PDF document text
    • https://www.audioclinica.pt/wp-content/plugins/super-forms/uploads/php/files/lkoskeldsntnl6irn11b3hld5e/bawesinugufikemolugozosor.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=brincadeiras+divertidas+para+retiroPDF 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_off000100ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100EC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011903.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11903 10580 bytes
SHA-256: 9b24d13af907b94ee9e7061b29f2364d608c18cb5a71540a557b01bafecafc6f
font_02_sfnt_off00013155.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13155 19260 bytes
SHA-256: 7443d343309fdf5a75b4860c6ce0dc020c96b9e924aa94470bdc323eeb861454