Malicious PDF — malware analysis report

Static analysis result for SHA-256 f68cc1763555c5d1…

MALICIOUS

PDF

124.9 KB Created: 2021-06-18 10:24:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-24
MD5: c474d8253bcc56563c9611f10e8af982 SHA-1: 8ee409d7f171ad79d97b1ee3405993bc605e5fca SHA-256: f68cc1763555c5d145bb0f98ad2fca3f57f67b8859dfe69a0022c1dd153862ae
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document was flagged as malicious by an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://transmar.biz/ckfinder/userfiles/files/nuvujojalesadebezorol.pdf In PDF document text
    • http://thm-holding.ru/wp-content/plugins/super-forms/uploads/php/files/342ad43c058a7040c218a339c927a6ee/58241183119.pdfIn PDF document text
    • https://yziact.fr/wp-content/plugins/super-forms/uploads/php/files/l1lc21ef5tj5b7e4tgj8n3muov/basowebagi.pdfIn PDF document text
    • http://jatyn.cn/upfiles/202105/file/1620602308.pdfIn PDF document text
    • https://jollytime.ru/wp-content/plugins/super-forms/uploads/php/files/4ec32b4a352f12979250e1cad8f7f7e5/petofagus.pdfIn PDF document text
    • http://avtoarka.ru/wp-content/plugins/super-forms/uploads/php/files/a7b00a2023a7242bc9ffe0078e6fd915/kasubirizo.pdfIn PDF document text
    • http://mirrorgallery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608091932cddc---poxolawekotepaziruruvig.pdfIn PDF document text
    • http://ebiocell.com/uploadfile/file/%5C/2021052609184525.pdfIn PDF document text
    • https://deltagroup.bg/uploads/file/19997673264.pdfIn PDF document text
    • https://kayakbranson.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609cda4479321---88295245989.pdfIn PDF document text
    • https://ballestermultiservicios.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b3f0005f594---32115328137.pdfIn PDF document text
    • http://interiorconsignments.com/media/file/dipipu.pdfIn PDF document text
    • https://ambulatorioveterinariosismondi.eu/file/83804317677.pdfIn PDF document text
    • https://carparts-fixture.com/file/file/kutasononazemufileja.pdfIn PDF document text
    • http://tokyoto.pl/UserFiles/file/15196995009.pdfIn PDF document text
    • http://re-view.online/fckFiles/file/4303299626.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=intermediate+accounting+volume+3+robles+empleo+pdfPDF 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00019c89.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x19C89 5660 bytes
SHA-256: ca2db664366fbb508cb05e84b1b9bce3fe900e04ef0f7a2c9e0ec11e5739c05b
font_01_sfnt_off0001afa8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1AFA8 11604 bytes
SHA-256: 414954f377d83fd05022d598c26afcd1d9a6e431e756d1a6ce6bd497a708b3e4
font_02_sfnt_off0001d5d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1D5D9 4324 bytes
SHA-256: 9f355172d696dda274cac500966718f112ce76951f19577ac4888987ea6471b2