Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8b7fe6323a4d65f…

MALICIOUS

PDF

70.5 KB Created: 2021-04-02 22:26:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: 5fd62e9ceb0cabfd608679824004ac3a SHA-1: 5bce075e3503941f09b27b0d41444686bd4d4714 SHA-256: b8b7fe6323a4d65fda58f248badaf9915d10f34615b79cb969b0fe914d6b1ec3
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a large number of embedded links, many of which point to disposable hosting and redirector infrastructure, indicating a link farm designed to distribute traffic to potentially malicious sites. The heuristic 'PDF_MALICIOUS_REDIRECTOR_LINK' specifically flags a URL leading to known malicious infrastructure. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 5

  • 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://dafemum.ru/strik?utm_term=industrial+revolution+dbq+essay+answer+key In PDF document text
    • https://cdn-cms.f-static.net/uploads/4501659/normal_6054cc6436af6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4367951/normal_5fd646e9ac455.pdfIn PDF document text
    • http://tonagruz.ru/how_to_create_sales_targets5ggle.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470543/normal_6014ca8f2e2e6.pdfIn PDF document text
    • http://muvepifare.mygamesonline.org/international_accounting_standards_list.pdfIn PDF document text
    • http://vumonivaxozutod.mypressonline.com/jonsered_525_chainsaw_parts_diagram.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4448558/normal_600bdd389f888.pdfIn PDF document text
    • http://exampl1214.com/example_referee_report_for_job_applicationwn5o9.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4370077/normal_6051ebd769f1a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4403807/normal_60437ab56e982.pdfIn PDF document text
    • https://wujojebexubab.weebly.com/uploads/1/3/1/3/131380870/maratojufo.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4383475/normal_5ffdb1fa80d56.pdfIn PDF document text
    • http://fipagolanikobax.mygamesonline.org/que_es_preeclampsia.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470699/normal_60459c8fea5eb.pdfIn PDF document text
    • https://litepuvib.weebly.com/uploads/1/3/4/7/134741427/fa77c036b2a4fa.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4474465/normal_5feb914348b39.pdfIn PDF document text
    • http://parrrtner.xyz/dubixipepasenifii79fu.pdfIn PDF document text
    • http://afracheat6.xyz/wefafuxanaxunubujuvoku5ez98.pdfIn PDF document text
    • http://riwuvodobopexu.mywebcommunity.org/approaches_of_teaching_english_language.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/bisiku/63143581854.pdfIn PDF document text
    • https://s3.amazonaws.com/loneminovu/bimixarizaxakenemelewobi.pdfIn PDF document text
    • http://wepunulirepobi.myartsonline.com/russian_alphabet_practice_sheets.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_off0000d7cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7CB 5340 bytes
SHA-256: 909746998a83a84b551b0b859dce2f5493acdf43cea91433ab272e509858308c
font_01_sfnt_off0000ea16.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA16 9948 bytes
SHA-256: 95aa5fc1383bc43ef7c0383f709344610e99f42a1de2e1b3e17c9696fa57d092