Malicious PDF — malware analysis report

Static analysis result for SHA-256 4fb34b6795255ac7…

MALICIOUS

PDF

75.7 KB Created: 2021-04-17 15:39:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: a3ac2a5036a1edcce4e1931aeea73db4 SHA-1: 2209820c2625fa86b082b5ab662993fc18119126 SHA-256: 4fb34b6795255ac72dfcac028e1293ba747a887b0540fa0d371c897f71e32cd6
196 Risk Score

Malware Insights

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

The PDF contains numerous external links, many of which point to SEO redirectors designed to phish for information or distribute malware. The heuristic PDF_SEO_LINK_FARM and PDF_SEO_UTM_REDIRECTOR_LINK indicate a deliberate attempt to create a link farm for malicious purposes. The ML classifier and ClamAV detection further confirm the malicious nature of the file, with the primary IOC being the redirector URL.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://dugedepap.ru/strik?utm_term=how+to+be+a+site+reliability+engineer PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4372358/normal_60135e0d66087.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4404725/normal_5ff3ee58309a5.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4481985/normal_60027ebad8a6b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4451945/normal_6040c175cb7c9.pdfIn PDF document text
    • http://sozerujodurepef.22web.org/10510389058.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4418567/normal_5ff0a1dfbe8f2.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4503767/normal_5fe35a620aeb7.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4451555/normal_60450bd1789cf.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://pimokizogo.epizy.com/chapter_20_building_vocabulary_politics_of_the_roaring_twenties.pdfIn PDF document text
    • https://s3.amazonaws.com/fajonubinomeder/90627305413.pdfIn PDF document text
    • https://s3.amazonaws.com/niporofez/56393650757.pdfIn PDF document text
    • https://s3.amazonaws.com/gumegulaxi/star_wars_ahsoka_tano_actor.pdfIn PDF document text
    • https://s3.amazonaws.com/panalipolifod/tepulorito.pdfIn PDF document text
    • https://25cf7bc6-226b-4013-96fa-c64d334b7dac.filesusr.com/ugd/317e1a_ddba214e36404de888dcb69011dbac5b.pdf?index=trueIn PDF document text
    • http://ziboporo.epizy.com/76066043870.pdfIn PDF document text
    • https://s3.amazonaws.com/degisapemifa/gastroenteritis_guidelines.pdfIn PDF document text
    • https://s3.amazonaws.com/wovedukevikov/74508728961.pdfIn PDF document text
    • https://s3.amazonaws.com/rojalexipokadaz/braidwood_central_school_uniform.pdfIn PDF document text
    • https://28546a20-d0cc-4b82-bb4f-6711990cd5a3.filesusr.com/ugd/0bcf16_71bdb063831949f294e962ea1a655f70.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/gosete/commvault_deduplication_ratio_report.pdfIn PDF document text
    • https://s3.amazonaws.com/wupuxus/acrylic_mirror_sheet_6ft_x_4ft.pdfIn PDF document text
    • https://s3.amazonaws.com/zesixefe/wenizawemakejiluk.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_off0000ebc5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBC5 5148 bytes
SHA-256: c29d7de30c04ec2d0fbb3be10080448255fc02e34d78ec13b7764c2df4e3476f
font_01_sfnt_off0000fd6b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD6B 10620 bytes
SHA-256: b9e727536a56d6bf670afb026e63ee68b791cd6b1d88408e7fb0de110e6c4766