Malicious PDF — malware analysis report

Static analysis result for SHA-256 d8c4c3072b2abd87…

MALICIOUS

PDF

71.6 KB Created: 2021-04-22 19:45:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: 96ac40ae7867c6edbc8f420d92d697e5 SHA-1: dcae6b503c8de9a5d6e86c6bd3df8d7fd3bb1b82 SHA-256: d8c4c3072b2abd87224e130bebaacee7279a01cb842b818ae0a6fcd3205a3bdb
244 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by multiple heuristics and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, containing numerous embedded URLs pointing to external PDF documents hosted on various domains, some of which are identified as disposable. One critical heuristic specifically noted a link to known malicious redirector infrastructure, suggesting these links may lead to phishing or malware distribution. The presence of these links and the overall structure strongly suggest an attempt to manipulate search engine results or distribute malicious content indirectly.

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 links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://yafferge.ru/strik?utm_term=schaum%2527s+physics+answers In PDF document text
    • https://cdn-cms.f-static.net/uploads/4497079/normal_6022a9d42de38.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4481518/normal_5ff90654cf981.pdfIn PDF document text
    • http://dipazekonowa.mypressonline.com/briggs_and_stratton_625_series_190cc_service_manual.pdfIn PDF document text
    • https://ralixuviromod.weebly.com/uploads/1/3/5/3/135345966/6755738.pdfIn PDF document text
    • https://fatilisuwojumo.weebly.com/uploads/1/3/4/6/134652656/7426036.pdfIn PDF document text
    • http://i-men.ru/latin_writing_for_websites1wi80.pdfIn PDF document text
    • http://universal-kirov.ru/all_of_me_clarinet_sheet_music_easyla59m.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4384835/normal_60076f5a17755.pdfIn PDF document text
    • https://vugogirofezufus.weebly.com/uploads/1/3/4/3/134355312/ba4d304.pdfIn PDF document text
    • http://universityru.fun/maths_subtraction_worksheets_for_grade_4vr9ad.pdfIn PDF document text
    • http://fidafevemikiwe.mywebcommunity.org/22287554328.pdfIn PDF document text
    • http://kvrovk.xyz/73231136999cak1h.pdfIn PDF document text
    • https://fupozivu.weebly.com/uploads/1/3/5/3/135316658/7687509.pdfIn PDF document text
    • http://cadenalia.com/angeles_y_demonios_libro_gratishuiqc.pdfIn PDF document text
    • http://lnstagramverifiedbadge-media.com/36541083535n0edo.pdfIn PDF document text
    • http://meetly.space/cake_baking_business_planqlzbc.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://c1908cc8-b41e-4b5b-ab1c-53d28a7f2745.filesusr.com/ugd/913720_cba685ef664c40ecb2c51ca2f67e2805.pdf?index=trueIn PDF document text
    • https://75ca6b5e-a470-4e0e-8004-b00a9f1721b4.filesusr.com/ugd/1e4819_45cbe44cbbb343c69db5e0fe2d83d70d.pdf?index=trueIn PDF document text
    • http://xiwozoget.atwebpages.com/how_to_analyze_an_advertisement.pdfIn PDF document text
    • https://8f1c0ae7-1ba6-4c51-a623-4d29f5e3aebb.filesusr.com/ugd/c1615c_9c5216e76d874c72ac2437b1701ce691.pdf?index=trueIn 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_off0000d923.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD923 5472 bytes
SHA-256: 4f17d7b3af7f504c2455b198dfd1922b69f574a6fab563fac6ad0eb6d6c1ac56
font_01_sfnt_off0000ebb9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBB9 11112 bytes
SHA-256: 89016f4dbaadc5c09268fa9814669e594ea3895e1597b2a82288544a90eefcc8