Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4102eb9ab9dc518…

MALICIOUS

PDF

77.7 KB Created: 2021-02-23 07:31:27 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: cbbf40e5e42a892de70a7ec60734a074 SHA-1: d7c311ec641d2bf83d559d9566322d955b3596ef SHA-256: b4102eb9ab9dc51836191c6d494e349aea12980dbcb8d2be908ab7138a8f43c1
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF contains a large number of external links, many pointing to disposable domains, indicating a link farm or SEO manipulation tactic. The ML classifier strongly flagged this PDF as malicious, and the presence of numerous external links suggests it may be used to distribute further malicious content or lead users to phishing sites. The document body is heavily obfuscated and contains what appears to be metadata rather than user-readable content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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://seumenha.ru/wix?keyword=2+elements+and+compounds+2.1+atoms+worksheet+answer+key PDF link annotation
    • http://kiduzat.iblogger.org/figita.pdfIn PDF document text
    • https://cdn.sqhk.co/gulizate/F4wihii/89827136120.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4496374/normal_5fd288f9327fa.pdfIn PDF document text
    • http://sizegivip.22web.org/libekomomomowulatidobogor.pdfIn PDF document text
    • https://cdn.sqhk.co/xapawavuma/YggSjhl/rum_balls_with_vanilla_wafers.pdfIn PDF document text
    • https://doxefifuz.weebly.com/uploads/1/3/0/9/130969363/5506488.pdfIn PDF document text
    • https://cdn.sqhk.co/tajiwikiter/gchjhaT/94612526089.pdfIn PDF document text
    • http://jumbochecker.com/how_to_reset_my_ellipsis_jetpacktliw3.pdfIn PDF document text
    • http://brumbum3.xyz/bosch_tassimo_coffee_machine_instruction_manual3lwfr.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4482405/normal_5fee184d54149.pdfIn PDF document text
    • http://instasurprise.online/koxigekajozumired24ajz.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4376120/normal_6005f37edfc3e.pdfIn PDF document text
    • https://cdn.sqhk.co/fimegasaz/bhg5zjg/mtv_the_maxx_streaming.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://riwugenesujo.epizy.com/red_cross_first_aid_refresher_course.pdfIn PDF document text
    • https://s3.amazonaws.com/vovabagubajegeb/vozeseja.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_off0000f347.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF347 5692 bytes
SHA-256: 81ae6acc003e6179359b59b1c1e51ee5508b0b94976644c0bb3f369453b49006
font_01_sfnt_off00010698.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10698 10200 bytes
SHA-256: ba698c7068f66e68f0053937ef1b4f894de3ffd310a2b8baa291a11ac32aaa22

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