Malicious PDF — malware analysis report

Static analysis result for SHA-256 66b2df85e9f528ae…

MALICIOUS

PDF

84.3 KB Created: 2021-05-22 01:04:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: b4503c2149c23d31152fcb39289db75a SHA-1: 297653af2418609d6f973472c05cfdc142e41de3 SHA-256: 66b2df85e9f528ae11d48b168cfd587f263b19302f2e7a8698da8c981e98f421
186 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains a large number of external links, many hosted on disposable domains, suggesting a link farm or SEO manipulation tactic. The document body, though partially corrupted, contains text related to "Ejercicios raiz cuadrada exacta" and metadata from wkhtmltopdf, which is likely used to generate the PDF to lure unsuspecting users to malicious or spam websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://nipisod.ru/strik?utm_term=ejercicios+raiz+cuadrada+exacta PDF link annotation
    • https://wefolukozik.weebly.com/uploads/1/3/1/4/131406413/jijufoxafupejalej.pdfIn PDF document text
    • https://nemaxololele.weebly.com/uploads/1/3/5/3/135304154/41955.pdfIn PDF document text
    • https://bamususifilozok.weebly.com/uploads/1/3/1/3/131383301/ca59318.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4456728/normal_601384cf759cb.pdfIn PDF document text
    • https://sibemawiwojaro.weebly.com/uploads/1/3/4/8/134887292/fb38d7f96.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4377905/normal_60461ea4926e2.pdfIn PDF document text
    • https://tiwenevudadag.weebly.com/uploads/1/3/4/7/134715745/faxamipigajoxom.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4459170/normal_601eea053ad7c.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4368956/normal_6006a443d8283.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4367964/normal_6022c46577999.pdfIn PDF document text
    • https://muwigoxafom.weebly.com/uploads/1/3/4/8/134869335/9abed9.pdfIn PDF document text
    • https://pobogovowot.weebly.com/uploads/1/3/5/3/135323888/c17b5c93d35b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4454306/normal_606cabc4c4ae2.pdfIn PDF document text
    • https://vidimepimexuja.weebly.com/uploads/1/3/4/6/134626803/deremumarovixow_jifaru.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4422643/normal_6067da2075a84.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4372373/normal_5fde2f1066462.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4483365/normal_604460c3a32d4.pdfIn PDF document text
    • https://pesenulowujef.weebly.com/uploads/1/3/5/3/135325158/4607889.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://fedorahosted.org/lohitIn PDF document text
    • https://s3.amazonaws.com/fogibi/70410573402.pdfIn PDF document text
    • https://s3.amazonaws.com/gurowozenupifi/venejalevijagexevaretaxo.pdfIn PDF document text
    • https://s3.amazonaws.com/kawotexulozax/16248621231.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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000eb60.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB60 5052 bytes
SHA-256: 580ac668863f5887cae102e9ea91f0bf08852a88a84fcca2cc7e251ed5db047a
font_01_sfnt_off0000fcad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCAD 1608 bytes
SHA-256: 5998e4e3b8911ddb053f9e3434b05fcd4c574a44ae7cee432541ac35685ca583
font_02_sfnt_off0001053b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1053B 11860 bytes
SHA-256: a57ca408e5e9f15b2312393a16a10a3dcb3972a7c73ab335f177a62a421b5bfb
font_03_sfnt_off00012c23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C23 16100 bytes
SHA-256: d98a9309e076b13835c6659d635ae6c9662cc733e578b44ec6f104cfef2f50ae

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