Malicious PDF — malware analysis report

Static analysis result for SHA-256 35f2b55e11e5017d…

MALICIOUS

PDF

80.5 KB Created: 2021-09-15 23:23:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: c255f54d726a2aaa20043d3277278c67 SHA-1: b0d577c7352b73d975d71427b3ec5aef8d7652b2 SHA-256: 35f2b55e11e5017db508d09c21bb7cde450479348af84eba63d6ceeeb3e43ddd
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ClamAV as a phishing trojan and by an ML classifier. It contains numerous embedded URLs that form a link farm, with several pointing to compromised WordPress sites or disposable hosting. The presence of these links suggests the document's primary purpose is to redirect users to external malicious sites, likely for phishing or to download further malware. No scripts were extracted, but the PDF structure and URL patterns are indicative of a malicious campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://krisoc.ru/uplcv?utm_term=airline+tycoon+deluxe+android PDF link annotation
    • http://ornito-silesia.eu/userfiles/file/935648755.pdfIn PDF document text
    • http://cudicio.it/images/file/woxuze.pdfIn PDF document text
    • http://ags-sib.ru/ckfinder/userfiles/files/rokitomojirofuz.pdfIn PDF document text
    • http://sushiyaslo.com/uploads/files/xamegowadolukamana.pdfIn PDF document text
    • http://nsmpublicschool.org/slbdavbatala/userfiles/file/xisefajaxozo.pdfIn PDF document text
    • http://anm-av.de/uploads/files/mebat.pdfIn PDF document text
    • http://drvision.org/wp-content/plugins/formcraft/file-upload/server/content/files/16133029b7f0ba---fifezijimigodixaj.pdfIn PDF document text
    • http://burchiellati.com/file_fck/file/72629819125.pdfIn PDF document text
    • https://dichvuhappyhouse.com/upload/files/nuxodesitebija.pdfIn PDF document text
    • https://store-connector.com/_upload_bilder/_filemanager/file/puwefifipepajigojebibujen.pdfIn PDF document text
    • http://aaykpn.com/uploads/editor/files/jikopevexuvisaj.pdfIn PDF document text
    • https://thietkewebseo.com/webroot/img/files/bujobugibatezepivaj.pdfIn PDF document text
    • http://asremajazi.com/uploads/files/42365500163.pdfIn PDF document text
    • http://geotersrl.it/file/81825465823.pdfIn PDF document text
    • http://lionsmarsala.it/userfiles/files/58352204735.pdfIn PDF document text
    • https://99shayari.in/userfiles/files/86106140326.pdfIn PDF document text
    • https://www.elektrobetrieb-scholz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613ad1b49a358---jusokeruxoruwolakarumo.pdfIn PDF document text
    • http://bluecreator.biz/ckfinder/userfiles/files/soxadorugit.pdfIn PDF document text
    • http://hotel-ambassador-nice.com/upload/files/razuwenameliz.pdfIn PDF document text
    • http://chinajnbt.com/images/upload/File/moganafo.pdfIn PDF document text
    • http://pro-elec.ru/ckfinder/userfiles/files/mowobivewopafoko.pdfIn PDF document text
    • http://headlinesdinerla.com/uploads/files/dopubajisixumujobusu.pdfIn PDF document text
    • https://fmpride.com/wp-content/plugins/super-forms/uploads/php/files/c1ef819558bba0205b070c1b187f5be5/76691334096.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_off0000d488.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD488 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ec9a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC9A 18408 bytes
SHA-256: 2e09a47445fb61fcaec7b3c8c3be6f5c7ecc079a4727604ae2fec96027032e21
font_02_sfnt_off00011c67.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C67 10492 bytes
SHA-256: 677153a9a4df9a12f05abfd479622ae39a575dce66cf140502858950b91e83b5