Malicious PDF — malware analysis report

Static analysis result for SHA-256 a2d916b6715787ac…

MALICIOUS

PDF

73.1 KB Created: 2021-05-27 03:57:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-05
MD5: 79e7a9e67c3a2293f7a2ecbf218e1a19 SHA-1: 4aac9386288068de338ea8603643d45253ea7d57 SHA-256: a2d916b6715787ac1e928881f8dcf0fde43f4400fe1dc578c4d0d0970affe0ad
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links to external websites, many of which are hosted on compromised CMS uploads or disposable hosting, indicating a link farm for malicious purposes. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. The document body, though heavily obfuscated, contains metadata related to wkhtmltopdf and a search query, suggesting it might be a lure to disguise the malicious links.

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 http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160aad028257f6---7467678582.pdf In PDF document text
    • https://trimix.bg/UserFiles/File/21903318346.pdfIn PDF document text
    • http://fixmyhelicopter.com/project-new/christianbook/upload_images/file/nasugi.pdfIn PDF document text
    • http://discarga.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f9e2aaca9b---89839854200.pdfIn PDF document text
    • https://sckstone.com/wp-content/plugins/super-forms/uploads/php/files/0ecbfae608242656adf90d1b3cf86bf1/34136867641.pdfIn PDF document text
    • http://alphasigmaoverseas.com/userfiles/file/74694041849.pdfIn PDF document text
    • http://pmdrecycling.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa45c1a8b6a---ferodiluxabezoke.pdfIn PDF document text
    • http://www.rec39.ru/wp-content/plugins/super-forms/uploads/php/files/d7434b8d3e7095ea9db2cb767d1ea405/fusosowepewosuvafev.pdfIn PDF document text
    • http://www.scmphotography.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1606cf3ccc4d33---zivuvenovorisa.pdfIn PDF document text
    • https://www.andeanskyline.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609dcdbde0ea7---85977432057.pdfIn PDF document text
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/4277efd1c38917c7a1e2450c803239d6/12502716144.pdfIn PDF document text
    • http://dom-nenilovo.ru/wp-content/plugins/super-forms/uploads/php/files/b96119186d145b5544d5abf06170e214/tisuguxek.pdfIn PDF document text
    • https://pluckywize.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a49f383a18---tiwevalowoxixefuruke.pdfIn PDF document text
    • https://www.quatainvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608f91e96f2be---93333670027.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/2k8fgn5j2dndkgkn6ttu1k7c21/30124240072.pdfIn PDF document text
    • http://teplospectr.ru/images/files/wijomi.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/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=how+much+does+a+plastic+sandwich+bag+weigh+in+gramsPDF 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_off0000dfbc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFBC 5680 bytes
SHA-256: 6becaa7dcce5f1b28ca1d6cc851575af235b48997bb65f2267721fb5bd728a5a
font_01_sfnt_off0000f2f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2F1 10608 bytes
SHA-256: b3a53fd6599715120ab7a6d9a45f6da35472cd20f6f191acd904bfe853e616bb