Malicious PDF — malware analysis report

Static analysis result for SHA-256 77b8b256e64969e2…

MALICIOUS

PDF

81.1 KB Created: 2021-09-07 09:25:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: a8a9bd6dbd852447705d04ce96f3d7cf SHA-1: 31a67ba3bc500668933722e25bf8137ac663c582 SHA-256: 77b8b256e64969e28bde5feb78fd9a6c3a8a381d33e80b75cf0fb4ff852a945b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The 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 URLs pointing to compromised WordPress sites and other disposable hosting, suggesting it's used to distribute phishing content or further malware. The presence of PDF-specific heuristics like 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' reinforces this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://catamma.ru/uplcv?utm_term=should+shouldn%27t+worksheet PDF link annotation
    • https://eagle-aviation.com/userfiles/files/10098157011.pdfIn PDF document text
    • http://valdhans.cz/userfiles/file/70399587329.pdfIn PDF document text
    • https://zd-zeta.com/uploads/files/202109061953287003.pdfIn PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1613394bb54cdd---jepob.pdfIn PDF document text
    • http://victorylimo1.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073d10bdcb7f---51982460011.pdfIn PDF document text
    • https://divinenine.net/userfiles/file/51829313759.pdfIn PDF document text
    • https://iohrp.org/f_files/files/12501858534.pdfIn PDF document text
    • https://guclupin.com/calisma2/files/uploads/24915879435.pdfIn PDF document text
    • http://www.unidacardoso.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606d10c82bfa9---diduvukigipiwuwapemurotig.pdfIn PDF document text
    • https://cffcommunications.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1/1607c64f031a19---92981351232.pdfIn PDF document text
    • https://amenagementsoleil.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084d9ea2c004---vopamonunejunid.pdfIn PDF document text
    • https://creativitagh.com/pevron/www/img/file/28310342847.pdfIn PDF document text
    • https://kmkmekanik.com/upload/ckfinder/files/74419183298.pdfIn PDF document text
    • https://action-roofing.com/wp-content/plugins/super-forms/uploads/php/files/c7198ae6d3d8c0cc83fffb5aadfd9b80/59904908162.pdfIn PDF document text
    • https://rclurie.com/wp-content/plugins/super-forms/uploads/php/files/c0d1d3ba219265957705b612885734bd/11670541035.pdfIn PDF document text
    • https://wintechindia.in/ckfinder/userfiles/files/fidavulejoga.pdfIn PDF document text
    • http://krukaiart.com/userfiles/files/23362303350.pdfIn PDF document text
    • http://www.medicalalliedtraining.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082c5a12cf65---digukipo.pdfIn PDF document text
    • http://davidhammerstein.org/ckfinder/userfiles/files/wudadijonunaderub.pdfIn PDF document text
    • http://sapientgenerator.ru/files/userfiles/files/velevutowetisupane.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a4596e8ec5e---guladadefijusi.pdfIn PDF document text
    • https://mobistore.co.nz/wp-content/plugins/super-forms/uploads/php/files/90217859c7efad33e20bc381c80f1d1f/tezoxagib.pdfIn PDF document text
    • https://www.vedaaz.com/wp-content/plugins/super-forms/uploads/php/files/f18aea4787437cb6a16ad7a0297f79ae/95480418444.pdfIn PDF document text
    • http://redwoodpwr.com/wp-content/plugins/super-forms/uploads/php/files/eujp72aknk8ggdb1pidcncq5s5/40916335591.pdfIn PDF document text
    • http://cdhsalumni.com/clients/28864/File/junajevijamuzosezefatoton.pdfIn PDF document text
    • http://geo-equipe.it/userfiles/files/gaparozexozev.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_off0000daf2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAF2 10480 bytes
SHA-256: 468dd0ba1c6182f2a1cadfc70e1870f3fd1a38238f9c8629d6497fc1133d460b
font_01_sfnt_off0000f2db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2DB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010aed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AED 17084 bytes
SHA-256: 4a9094e4951e8c4f764972d2d8ee0949ee2a6e59fb1c0f30377174c45865121e

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