Malicious PDF — malware analysis report

Static analysis result for SHA-256 a039138b2dea425f…

MALICIOUS

PDF

68.7 KB Created: 2021-05-05 01:21:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-12
MD5: 4bec8742d3273172858e8ef939ee6dd2 SHA-1: 226aa8ce07e75da0b9cd77021207eff3924760ab SHA-256: a039138b2dea425fc9524e5a05cf727153da2c41dfac08f9125d9212c0ee7df9
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution T1059.007 JavaScript

This PDF 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 embedded URLs pointing to compromised WordPress sites and other domains, likely serving as a distribution point for phishing content or further malware. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://yarsan.ru/wp-content/plugins/super-forms/uploads/php/files/28f29f5946a9879157be4a75e3957caa/59762278761.pdf In PDF document text
    • https://gfow.om/wp-content/plugins/super-forms/uploads/php/files/vbn8cvunkvihbc6vk0j68l1918/50586807653.pdfIn PDF document text
    • http://intechsol.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1607f2baf84cc0---33850664531.pdfIn PDF document text
    • https://www.kiteschule-eckernfoerde.de/wp-content/plugins/formcraft/file-upload/server/content/files/160858399e2b1b---48981145971.pdfIn PDF document text
    • https://swimproject.eu/wp-content/plugins/super-forms/uploads/php/files/3ccddb1e2aaae8332bf83c7edac85ddf/lojetegufibiw.pdfIn PDF document text
    • https://bellevuecommunityfoodbank.org/wp-content/plugins/super-forms/uploads/php/files/c85ca5db87a871df974e2dfc37a6ca9f/61772780109.pdfIn PDF document text
    • https://alihuata.com/userfiles/file/rodegexisefudofebatapi.pdfIn PDF document text
    • https://hmjrgoldhockey.org/wp-content/plugins/super-forms/uploads/php/files/7e7494e8a2dbd13d609fea745cabf402/99395613314.pdfIn PDF document text
    • https://costumeworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/160864b3e125e9---nitebofixoxegabeduf.pdfIn PDF document text
    • http://nd-58.ru/wp-content/plugins/super-forms/uploads/php/files/542f16aebc0b77b6670250be78fb52d9/89682299062.pdfIn PDF document text
    • http://amon-syotengai.com/userfiles/file/nidaje.pdfIn PDF document text
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/7e390f4bcb3435d9afdc5eda39a7c479/tuvinogezeturu.pdfIn PDF document text
    • https://www.revistadefiesta.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608013d732523---45009437192.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=girl+baby+shower+invitations+blank+templatesPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ce3f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE3F 5548 bytes
SHA-256: 36e1ead19f9daf1c60c902e3ce0478c5f7f7986ec7fc419479416a3d2b9b08ae
font_01_sfnt_off0000e10c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE10C 10996 bytes
SHA-256: 829439c57be888f84430c08dc8db4aababe163c64727cb6e9bf735fc5136e03d