Malicious PDF — malware analysis report

Static analysis result for SHA-256 28e535d2788c8aa1…

MALICIOUS

PDF

73.1 KB Created: 2021-02-19 08:47:21 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-17
MD5: 41a42cf35a0898df5ef979bcd1ef80e5 SHA-1: ac1336fc79a89519ae12d6c22f0ed4ba3993b106 SHA-256: 28e535d2788c8aa1aa78a9f0b5b7f81aa6fe413d8f3a5875748dc7e91ade5405
252 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded links, many pointing to disposable domains and potentially malicious redirectors. Heuristics indicate this is a link farm designed for SEO manipulation or to distribute further malicious content. The ClamAV detection and ML classifier strongly suggest malicious intent, likely related to phishing or malware distribution via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 7

  • 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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=ccna+voice+exam+fees+in+india In PDF document text
    • https://cdn-cms.f-static.net/uploads/4372707/normal_6012435b68dce.pdfIn PDF document text
    • https://garegijewavib.weebly.com/uploads/1/3/4/3/134389285/danovesisimub-pelutojijujeke-sadopogiriwulun.pdfIn PDF document text
    • https://cdn.sqhk.co/toliximozupa/utsgjhZ/94530199971.pdfIn PDF document text
    • https://bujakisuka.weebly.com/uploads/1/3/2/6/132695398/gapede.pdfIn PDF document text
    • https://wurotifaji.weebly.com/uploads/1/3/4/3/134315076/7b9ae6c35671.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4420476/normal_602d0e79b11aa.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4444864/normal_5feb6c161ea4f.pdfIn PDF document text
    • https://cdn.sqhk.co/vemetafije/XUgfvMj/kotupanajowufasu.pdfIn PDF document text
    • http://javatow.22web.org/basic_geometry_vocabulary_worksheet.pdfIn PDF document text
    • https://cdn.sqhk.co/fomezawelud/dh1xghw/99055731357.pdfIn PDF document text
    • http://xiselegudiwip.iblogger.org/nutogexobekaritexeb.pdfIn PDF document text
    • https://cdn.sqhk.co/dederubap/EjiIGgi/61495737783.pdfIn PDF document text
    • https://vidimepimexuja.weebly.com/uploads/1/3/4/6/134626803/fuvupujetam_fazaf.pdfIn PDF document text
    • https://cdn.sqhk.co/tutabalero/hjcqG6T/83207470370.pdfIn PDF document text
    • http://zumedemuruva.22web.org/tazoraduvodaser.pdfIn PDF document text
    • https://balupelirotapos.weebly.com/uploads/1/3/2/6/132681476/duxakakuwo.pdfIn PDF document text
    • https://tobivuzulukimu.weebly.com/uploads/1/3/1/3/131384599/0b8cfbdb1.pdfIn PDF document text
    • https://sidedelozamuk.weebly.com/uploads/1/3/1/4/131482822/vuxotanojikud-puvibo.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://lojetewope.epizy.com/spreadsheet_ideas_for_budgeting.pdfIn PDF document text
    • https://s3.amazonaws.com/zizene/bpmn_notation_cheat_sheet.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_off0000e172.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE172 5072 bytes
SHA-256: ab27be565842dd60aca9156f1aeb4b0c9e16d2c5bbf31928c1667b0026b29530
font_01_sfnt_off0000f2ae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2AE 10996 bytes
SHA-256: 7c0457a3085908c8d9ffa49ff756ec972ec59a90842f90a73500a26040f97858