Malicious PDF — malware analysis report

Static analysis result for SHA-256 83a8b8a8ec043720…

MALICIOUS

PDF

80.6 KB Created: 2021-09-04 00:03:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 171dcdaef914fd6a2080c4ecef0ecb13 SHA-1: cd72c0e7820659eebd2765600ae556c3400233f0 SHA-256: 83a8b8a8ec043720e38aa2f395588f5f4d14397d8424fa4120af6fcd0346714e
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to compromised websites, identified by heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM'. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The primary attack pattern involves luring users through a malicious attachment to these compromised sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://crysiq.ru/uplcv?utm_term=comprehension+worksheet+for+grade+2+pdf PDF link annotation
    • https://ncfouting.com/wp-content/plugins/formcraft/file-upload/server/content/files/16111d4e4bc850---ruzatimogopoko.pdfIn PDF document text
    • http://michardardillier.com/ckfinder/userfiles/files/14379360961.pdfIn PDF document text
    • https://sunrise-photon.com/upfiles/editor/files/zexopogo.pdfIn PDF document text
    • https://kolbandibileklik.com/resimler/files/96790708053.pdfIn PDF document text
    • http://steclotildehorton.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16085eef93d306---tapedowilewinana.pdfIn PDF document text
    • http://www.moteco.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607a5c8dc8617---74860401101.pdfIn PDF document text
    • https://cemb.ca/upload/editor/file/84445585263.pdfIn PDF document text
    • http://navigator-nsk.ru/userfiles/file/tefasidedigosefeniwaluse.pdfIn PDF document text
    • https://www.hit-education.com/wp-content/plugins/super-forms/uploads/php/files/amjihqb4plpb8j5ogub7ejph1j/55340986563.pdfIn PDF document text
    • https://kientrucqhouse.com/uploads/image/files/79861181498.pdfIn PDF document text
    • https://oklogistic.lv/upload/file/jofasikufibowabaziwiz.pdfIn PDF document text
    • http://superplasticizer.cn/d/files/faxaxara.pdfIn PDF document text
    • http://royalleasingny.com/admin/images/file/84889673005.pdfIn PDF document text
    • http://www.julitolaschools.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bdd9ef25049---kerofibo.pdfIn PDF document text
    • http://quangphong.vn/uploads/image/files/96249472224.pdfIn PDF document text
    • http://xn--dlek-5qa.com/admin/UserFiles/file/jukurerokewiro.pdfIn PDF document text
    • https://sellos-mecanicos.com/wp-content/plugins/super-forms/uploads/php/files/2b4733b2795c989cea51a0d34e1477d9/62985120164.pdfIn PDF document text
    • https://postele-z-masivu.sk/ckfinder/userfiles/files/jumuvalazigobegol.pdfIn PDF document text
    • https://alienaquatics.com/home/gb/public_html/ckfinder/userfiles/files/wanumixexilivunomo.pdfIn PDF document text
    • http://philipsphotographystudio.com/65541790559.pdfIn PDF document text
    • http://www.ctnphrae.com/ckfinder/userfiles/files/29901032211.pdfIn PDF document text
    • https://firsatpin.com/calisma2/files/uploads/36314982900.pdfIn PDF document text
    • http://tootingtaxi.com/survey/userfiles/files/biwilegupubopulevive.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_off0000d6ad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD6AD 11228 bytes
SHA-256: 7ec4d1ea6b950967a86719f303134ba7517d7889137d0805a0c31ba82a12429b
font_01_sfnt_off0000f0bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0BB 16992 bytes
SHA-256: 1c0f10f4ec0553cc358c3a0337c489910d9518b8e63145a418bd6fb95b246c9d
font_02_sfnt_off00011c96.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C96 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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