Malicious PDF — malware analysis report

Static analysis result for SHA-256 41c5f5db5528f1d3…

MALICIOUS

PDF

78.2 KB Created: 2021-05-23 17:58:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-14
MD5: dc6e75b5bd42197ed1616230851fcf39 SHA-1: 9ffee5bce60760752eb859017bc2c365e5b25535 SHA-256: 41c5f5db5528f1d37c0f20017f473823b4632217527ceb77490a876e59662ddc
186 Risk Score

Malware Insights

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

The PDF document contains a large number of external links, many pointing to disposable hosting services, indicating a link farm designed to redirect users to malicious sites. The heuristic PDF_SEO_LINK_FARM and PDF_SEO_DISPOSABLE_LINK_FARM firings, along with the ClamAV detection and ML classifier, strongly suggest malicious intent. The primary malicious URL identified is https://mezovuduw.ru/strik, which is likely used for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://mezovuduw.ru/strik?utm_term=theme+ppt+%25C4%2591%25E1%25BA%25B9p+free PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4374009/normal_604f8c020aaec.pdfIn PDF document text
    • https://fibumexil.weebly.com/uploads/1/3/1/0/131070733/garalatagikemo_puvatediwaz.pdfIn PDF document text
    • https://gumopukuzi.weebly.com/uploads/1/3/4/4/134481114/luwarumumamedinoripu.pdfIn PDF document text
    • https://vazemewezasal.weebly.com/uploads/1/3/0/7/130775722/lejoruxuj-sufidafuk-sosujeniresifo.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4487916/normal_603a5e66e166b.pdfIn PDF document text
    • https://fotejisatowonu.weebly.com/uploads/1/3/2/3/132302873/jijefogozubumi.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4487641/normal_605b212bc00a4.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368991/normal_605ac5d704b35.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4486987/normal_604d3f06b4e1d.pdfIn PDF document text
    • https://sawotulexude.weebly.com/uploads/1/3/5/2/135298589/db032436b59bdf.pdfIn PDF document text
    • https://bizugejukuvav.weebly.com/uploads/1/3/4/3/134322279/gudejoner.pdfIn PDF document text
    • https://bagobizofenagex.weebly.com/uploads/1/3/4/7/134767931/dimowelo.pdfIn PDF document text
    • https://bixuduserar.weebly.com/uploads/1/3/4/8/134861961/bufulubugosobebaboki.pdfIn PDF document text
    • https://fexagire.weebly.com/uploads/1/3/0/7/130775556/wiwisexenerefix-xipasugij.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4404959/normal_6048737e5272a.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/c759af0c-693d-4c6c-9e3f-6cd906a2e03b/the_house_on_mango_street_chapter_14_summary.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3f48be9d-e485-4ede-a7a3-199375840c02/80549068211.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/759a9eaa-640c-4ff3-8178-0aa0ceaccea8/civilization_6_gathering_storm_contains_rise_and_fall.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/8e788d7e-bb16-47b9-9bfe-a1506e6351d0/la_estructura_de_la_magia_richard_bandler_y_john_grinder.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a056c76e-ed0d-4907-8b70-c605de5780b3/94212293349.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/7b54e833-dc39-47e7-8469-16e77251cd6c/98669996842.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/8acfc254-432d-4b1f-a1db-a66d28e29a2d/push_power_protect_sony_mhc-rg88.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_off0000ea2f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA2F 4960 bytes
SHA-256: 19c6a99f33ff18f7d7edf7ce0fa0e955f48d92aaf29ec5bee0b2ed155e29e1c0
font_01_sfnt_off0000faa5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAA5 21692 bytes
SHA-256: db0337b15d64d123e288fc649c1a9c142dca34ecf7081833789a8e8dc9720998