Malicious PDF — malware analysis report

Static analysis result for SHA-256 839561476db42f3d…

MALICIOUS

PDF

84.0 KB Created: 2021-02-06 00:03:36 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-15
MD5: b532fbfed1aa5afee0206ff00f24ab93 SHA-1: 4a6139b97a1881874714c76fdca19a0c33dc6162 SHA-256: 839561476db42f3da579a8c62e5459818613d1616874e29c5e1ab783e9e6af5a
186 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

This PDF file was identified as malicious by a machine learning classifier and ClamAV, indicating a high likelihood of malicious intent. It contains a large number of external links, many hosted on disposable domains or subdomains, suggesting a link farm or SEO spam operation designed to redirect users to potentially harmful content. The document body, though heavily obfuscated, contains references to 'middle school math concepts' and the authoring application 'wkhtmltopdf', which are likely lures to attract unsuspecting users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • 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://maypoin.ru/123?utm_term=middle+school+math+concepts PDF link annotation
    • https://cdn.sqhk.co/diratukuz/GjgQbw8/diversify_meaning_in_telugu.pdfIn PDF document text
    • https://kofuwirobunugob.weebly.com/uploads/1/3/4/3/134318534/lobox.pdfIn PDF document text
    • https://cdn.sqhk.co/dazulegug/iJcjjhg/15090420880.pdfIn PDF document text
    • https://cdn.sqhk.co/jawutuwek/W0QOvGA/wwe_smackdown_roster_wiki.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4426810/normal_5fddbc5887fb3.pdfIn PDF document text
    • https://geduwitanezuter.weebly.com/uploads/1/3/0/7/130738684/mapuv-runuvutozad-vufudam.pdfIn PDF document text
    • https://cdn.sqhk.co/vumivatuvi/Dhbjg3v/jugovaduvedexutomurov.pdfIn PDF document text
    • https://wewiruvikaju.weebly.com/uploads/1/3/0/7/130775929/xivirifubovo_mifej_dakok.pdfIn PDF document text
    • http://milesnires.xyz/31798253444t0xsf.pdfIn PDF document text
    • https://cdn.sqhk.co/dudugetogi/e9Cgehb/rex_sky_force_3d_best_settings.pdfIn PDF document text
    • https://pebawatiwokup.weebly.com/uploads/1/3/4/5/134576243/lotipojupapu.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4475219/normal_5fd2e5c844ee6.pdfIn PDF document text
    • https://cdn.sqhk.co/xonudutixova/djfqDw5/water_theme_parks_in_houston_texas.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010e5b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E5B 5224 bytes
SHA-256: f8cbfa01af98e37ebcc22f8f73853fd9f1b244bf82a9065112642164ced6d548
font_01_sfnt_off00012002.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12002 10268 bytes
SHA-256: 7cd8b41266de4cecce9ca4e03bc40b68a65edd4c6bb991e8f124f1bba7f5ac71

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