Malicious PDF — malware analysis report

Static analysis result for SHA-256 99c53f118e2a6e75…

MALICIOUS

PDF

78.9 KB Created: 2021-05-24 18:34:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: e8426c337b97cd4700a5ab15eb280c0b SHA-1: 4b1730a1f1e5c8f60b1b4705c47184fc353f2211 SHA-256: 99c53f118e2a6e75f57847aa28fb99bc752e7f4f69b8f85445e4c0a708b92b32
196 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 of which are SEO-optimized and redirect to a malicious domain. The primary lure appears to be a search result for '6th grade science textbook mcgraw hill pdf', which redirects to 'https://zajinet.ru/strik'. This suggests a phishing or scam campaign aiming to trick users into downloading potentially malicious content. No scripts were extracted, but the PDF structure and numerous external links indicate a malicious intent.

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
  • 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.
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • 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://zajinet.ru/strik?utm_term=6th+grade+science+textbook+mcgraw+hill+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4485704/normal_60676acc3e1fd.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4501193/normal_602f40f8bb130.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4479454/normal_6069115779e3c.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4421468/normal_5fde8f70ca1f7.pdfIn PDF document text
    • https://bofakodejo.weebly.com/uploads/1/3/4/2/134265658/ef3a622.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4370541/normal_601865cdd5fd7.pdfIn PDF document text
    • https://mikedexe.weebly.com/uploads/1/3/1/4/131452733/donaj_dupadedog_tipigaxuzebez_tewunogimokana.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4370071/normal_5fdd5ce43db17.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4413235/normal_5fcb9d05a7c01.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4365619/normal_604307dfa3eaf.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4381083/normal_6063dffb94b41.pdfIn PDF document text
    • https://zilonuxe.weebly.com/uploads/1/3/1/6/131637529/robofipovasifazego.pdfIn PDF document text
    • https://xerazagas.weebly.com/uploads/1/3/0/8/130813913/e71f6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4446915/normal_6019807e94ad6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4415080/normal_602920c2ed661.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/pizivurapab/what_is_better_real_id_or_enhanced_drivers_license.pdfIn PDF document text
    • https://s3.amazonaws.com/fulazelof/72937362612.pdfIn PDF document text
    • https://s3.amazonaws.com/buponuwebi/advertisers_gothic_light_font_free.pdfIn PDF document text
    • https://s3.amazonaws.com/remavuj/71595696112.pdfIn PDF document text
    • https://s3.amazonaws.com/zuwimadaneb/how_to_reset_the_oil_life_on_a_2012_toyota_highlander.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_off0000f6f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6F0 5992 bytes
SHA-256: dfa1397ed136f790f3b3963aa89ad753620eb3170e8569e44ece40eb06b59451
font_01_sfnt_off00010b40.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B40 10112 bytes
SHA-256: 23d64a5f326762a555fc1701567d5b712526d7b52dc5e2969305b419aa4ffcd6