Malicious PDF — malware analysis report

Static analysis result for SHA-256 a403fbe58c071e45…

MALICIOUS

PDF

76.3 KB Created: 2021-06-04 03:01:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-13
MD5: 0e0757bb62aec1b071d801e762475072 SHA-1: c92112761174c03b876e35eebb16b097550e2b7e SHA-256: a403fbe58c071e4558c8da7a8f5a64c30c5c036534b724fa8736eaf76a395ae8
186 Risk Score

Malware Insights

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

The PDF file contains a link farm pointing to numerous external PDF documents, with one primary URL being `https://jumiwimov.ru/123?utm_term=kra+appraisal+form+sample`. Heuristics indicate this is a link farm on disposable hosting, and ClamAV detection confirms it as a phishing trojan. The ML classifier also strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://jumiwimov.ru/123?utm_term=kra+appraisal+form+sample PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4369664/normal_602e9836e2f60.pdfIn PDF document text
    • https://kujoposa.weebly.com/uploads/1/3/1/4/131453526/e406666.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470839/normal_6011cffb1a196.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4402503/normal_6023491c78962.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4379374/normal_604ca51596541.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4411701/normal_6058f54049c69.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4406216/normal_5fe7cb70ab63e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4392439/normal_606e7e2a20858.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4445749/normal_5ff3d07be0074.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4461249/normal_602bf603bd903.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4410965/normal_5fc7ddd89b86e.pdfIn PDF document text
    • https://fizijoju.weebly.com/uploads/1/3/0/8/130814030/favurenabetomuw.pdfIn PDF document text
    • https://static.s123-cdn-static-d.com/uploads/4422884/normal_60b6e37dba516.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4375887/normal_606cd074b5c3a.pdfIn PDF document text
    • https://tudasuli.weebly.com/uploads/1/3/4/4/134403402/wibakopimo.pdfIn PDF document text
    • https://bejofiba.weebly.com/uploads/1/3/7/5/137501455/5545146.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4456391/normal_6061018799564.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://kipizasuzeda.pbworks.com/f/perfumes_the_a-z_guide_2018.pdfIn PDF document text
    • http://wuranosa.pbworks.com/f/26263625539.pdfIn PDF document text
    • http://lekuzax.pbworks.com/w/file/fetch/144419187/do_blue_dye_tests_always_have_a_faint_line.pdfIn PDF document text
    • http://sodopateduke.pbworks.com/w/file/fetch/144426267/muginaderomififuse.pdfIn PDF document text
    • http://gupiguna.pbworks.com/f/53945494176.pdfIn PDF document text
    • http://rimikupababo.pbworks.com/f/4595964766.pdfIn PDF document text
    • http://jesababa.pbworks.com/f/kadoxukarewogufik.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_off0000ed6c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED6C 5016 bytes
SHA-256: 737ed1ba51c6c757f63b33be49376ba5a54aca732ad24a4d5d5a0a5b1ed5b968
font_01_sfnt_off0000fe68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE68 11108 bytes
SHA-256: efceb7eb76357304f672a70af00d9017d2ba1238bf86953f78c9217c6833b19f