Malicious PDF — malware analysis report

Static analysis result for SHA-256 93bf24f4bf775dba…

MALICIOUS

PDF

73.5 KB Created: 2021-05-29 22:23:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: b1ea80b8d0f419d4ca7ba4e02f034bb0 SHA-1: c5bbc444d7775049465b451845316cb8ed5422ae SHA-256: 93bf24f4bf775dba3b28426f639c1e34f1842e572a81cb0ad9e0e81981986eca
244 Risk Score

Malware Insights

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

The PDF contains a large number of embedded links, many of which point to disposable hosting or known malicious redirectors. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body, though heavily obfuscated, appears to contain keywords related to exercises, suggesting a lure to disguise the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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
  • 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://crophysi.ru/strik?utm_term=ejercicios+campo+lexico+y+semantico+pdf In PDF document text
    • https://cdn-cms.f-static.net/uploads/4450148/normal_602f8c800bb09.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4415546/normal_606912bce09c6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4463791/normal_602b425fcdcbe.pdfIn PDF document text
    • https://dibigisilob.weebly.com/uploads/1/3/1/6/131607467/4653865.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4368250/normal_5fcebde5ce8b9.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4423714/normal_6049eb2113b5b.pdfIn PDF document text
    • https://wobusaxumezi.weebly.com/uploads/1/3/4/8/134881220/7967459.pdfIn PDF document text
    • https://kuzirorox.weebly.com/uploads/1/3/0/7/130775715/witurirazisotej.pdfIn PDF document text
    • https://velawavasikene.weebly.com/uploads/1/3/5/4/135400921/1878128.pdfIn PDF document text
    • https://womagojewe.weebly.com/uploads/1/3/5/9/135961056/f6222bf7464.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/87df74fd-f6d8-4624-8c84-d6ed797dd9df/bissell_little_green_clean_machine_manual.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/140eef71-46bd-490e-936b-9c973c62b00e/4039305130.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/bc238d8e-9f7b-4aec-9cba-b93f20d44edb/mrv_f340_alpine_amp_price.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f648487f-3bcc-4bc6-b8f8-8910fda9e773/rovukisabomezesoxo.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/2f54d795-a32e-4a55-a808-bf4ba41c3a8e/bold_jumping_spider_habitat.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/8595473a-e1db-4f16-aafd-a65c8d622c69/great_man_theory_of_leadership_strengths_and_weaknesses.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4e3fd513-1e82-4819-a78a-b6bcadd4d0ef/xotub.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a6430123-0d59-43cc-9bce-19993cf80a8e/agatha_christie_the_best_of_poirot_5_books_box_set_collection_pack.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/53964670-ff83-4e7a-b25a-1ced026ce81f/why_do_teeth_look_whiter_at_night.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/5a3ed723-59c9-47da-bd81-5847081fce60/webeloro.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_off0000de7e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE7E 5504 bytes
SHA-256: 5c36250243b8170904fff20145253e9a9beacf19ed977d75597c9ca385c45025
font_01_sfnt_off0000f13a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF13A 11564 bytes
SHA-256: 621c62d3b1673bfdbd5fdc247e6cb1cac4a2086c438a9b396aa13165fd1a5925