Malicious PDF — malware analysis report

Static analysis result for SHA-256 8fb54dc99f10e73c…

MALICIOUS

PDF

82.0 KB Created: 2021-09-12 11:20:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: c1f191494bd0f392122aa02fd433e55c SHA-1: 08a52d13be756eb6f286c5674df931dcd1b04d95 SHA-256: 8fb54dc99f10e73c6b74a8be7dde22a8859a9290f135db7586ffa3ed3e0887de
96 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to other PDF files hosted on various domains, many of which appear to be compromised or disposable. This structure suggests a link farm designed to lure users to potentially malicious content, possibly for SEO poisoning or phishing. The ML classifier strongly indicated maliciousness, supporting the assessment of a malicious PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 5

  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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 http://afslab.asia/upload/files/94021982446.pdf In PDF document text
    • https://khangle.vn/uploads/images/files/25964933972.pdfIn PDF document text
    • https://binarbaidfabrication.com/public_html/userfiles/file/vegejutozitirikal.pdfIn PDF document text
    • https://nullemont.fr/nullemont/ckfinder/userfiles/files/22572994746.pdfIn PDF document text
    • http://luberoff.com/userfiles/file/63607280985.pdfIn PDF document text
    • http://www.mvdisposal.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138f7479a4bc---99458592297.pdfIn PDF document text
    • http://www.sunaryem.com.tr/wp-content/plugins/super-forms/uploads/php/files/boogln1adr09gi335olvh72ue3/48576075034.pdfIn PDF document text
    • http://ownlines.com/upfiles/file/85453221399.pdfIn PDF document text
    • http://pickup-ws.com/userfiles/files/bujomubeviselusojowuziter.pdfIn PDF document text
    • http://lifeisartfoundation.org/sites/default/files/images/userfiles/file/84597285823.pdfIn PDF document text
    • https://lolakarimova.uz/ckfinder/userfiles/files/23231443083.pdfIn PDF document text
    • https://www.casestilistas.es/ckfinder/userfiles/files/simabiluzisaf.pdfIn PDF document text
    • https://kermanrooz.com/img/files/4262362885.pdfIn PDF document text
    • http://generaltubi.com/container/ckfiles/files/mujigik.pdfIn PDF document text
    • https://kede.org/userfiles/file/34499367514.pdfIn PDF document text
    • http://tolaniprojects.com/userfiles/file/95129753670.pdfIn PDF document text
    • https://duhocblueocean.vn/ckfinder/userfiles/files/47952000375.pdfIn PDF document text
    • http://phongthuydotho.vn/upload/files/zedopisozilomejisekope.pdfIn PDF document text
    • https://incense888.com/uploads/files/202109062129482066.pdfIn PDF document text
    • http://di-tech.kr/fckeditor/userfiles/file/dobilanomoxomamadigizufop.pdfIn PDF document text
    • http://lisaarkinlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/95510568695.pdfIn PDF document text
    • http://stkvn.ru/wp-content/plugins/super-forms/uploads/php/files/a5cf953ba259e4eab3bf8c6338fae737/37134256546.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=sims+freeplay+apk+mod+downloadPDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000db58.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB58 17672 bytes
SHA-256: 40ad08bf9aeb2e9e18d8c21347fbc5b76e20e32704f118c2f35e4feb7b7351fa
font_01_sfnt_off0001091b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1091B 10928 bytes
SHA-256: 3b918f8ac4a8899c63904e54374b7fff2f691859de20900e8bdf19780ada7c79
font_02_sfnt_off00012268.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12268 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1