Malicious PDF — malware analysis report

Static analysis result for SHA-256 5427623cd28ba2fc…

MALICIOUS

PDF

79.1 KB Created: 2021-06-05 13:14:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: 348b050eabc99e8f613bb98ae39c7b97 SHA-1: ad84c4987cfbce0b848c5c3785d5a03d95424ba4 SHA-256: 5427623cd28ba2fcbbb08429b3cef537d3c5cbac1edcba58092a684a0710fb1b
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file contains a large number of external links, many hosted on disposable domains, suggesting it is part of an SEO spam or link farm operation. The embedded content, though heavily obfuscated, appears to be related to 'Cambridge English exams', likely a lure to attract clicks. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://jumiwimov.ru/123?utm_term=cambridge+english+exams+pdf PDF link annotation
    • https://kexuminuki.weebly.com/uploads/1/3/4/3/134310960/kezaxaxaka-panituso.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4382972/normal_60431f152146f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4401692/normal_60190c279da5a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4446283/normal_602a366f396ed.pdfIn PDF document text
    • https://rofovotojoroko.weebly.com/uploads/1/3/4/8/134878837/a7c60a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4459165/normal_60683abe2310f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4481068/normal_60166e3879d4a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4420468/normal_6016d009b4785.pdfIn PDF document text
    • https://xafukulirodut.weebly.com/uploads/1/3/1/3/131379356/e5e5d2b4445a99.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4452385/normal_601ad233c00ab.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4417418/normal_5fe9f497086bb.pdfIn PDF document text
    • https://loruwowawerer.weebly.com/uploads/1/3/1/4/131483348/e015e091fb10.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4385634/normal_5fc979dc8cfd8.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/0a5a645e-b98c-4fe8-8a6d-86d088fa6189/15834841375.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f5d879b3-0829-4e48-99a0-b3ddd7235c90/59630399126.pdfIn PDF document text
    • http://zuvuzut.pbworks.com/f/krte_ilahi_mevlid_mp3_indir.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/554b378e-275e-4b03-ad45-a89def8a7c51/lovituve.pdfIn PDF document text
    • http://bemulopawed.pbworks.com/w/file/fetch/144469680/compound_words_worksheet_for_grade_2.pdfIn PDF document text
    • http://wuvebag.pbworks.com/f/vukusotimoralowu.pdfIn PDF document text
    • http://natizasex.pbworks.com/f/aiou_solved_assignment_2_code_417_spring_2020.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/48624c3d-6a22-4326-940f-25c0a05c5396/how_fast_upload_speed_do_i_need_for_zoom.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f61c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF61C 5568 bytes
SHA-256: 8f25701fefc32b5e7ccf06507711655326d5ccf784fcc8f60dde1f4f6c6ddde5
font_01_sfnt_off000108d6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108D6 11028 bytes
SHA-256: 408470499a34efa0e84ebd6dd89816ff6fa3ccb0ee293fa0bcd7af982c2c301d