Malicious PDF — malware analysis report

Static analysis result for SHA-256 fb4e993a31cf82be…

MALICIOUS

PDF

69.6 KB Created: 2021-02-08 00:53:42 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-12
MD5: eac14070b6b993d1a88886d12f4d9027 SHA-1: 9eb20a0aed06a93e55679dacc9c785d84d73e3cb SHA-256: fb4e993a31cf82be916b2627053166e729a32c3c5fb67ac36600fcc16c1e990a
126 Risk Score

Malware Insights

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

The PDF contains numerous external links, with one specifically pointing to 'jacksth.ru' and another to a link farm on disposable hosting. ClamAV and ML classifiers strongly indicate maliciousness, classifying it as a phishing trojan. The presence of embedded URLs and the nature of the heuristics suggest the PDF is intended to redirect users to malicious sites, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 5

  • 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 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://jacksth.ru/123?utm_term=fractions+decimals+and+percents+worksheet+pdf PDF link annotation
    • http://vedibekupuviru.iblogger.org/bosuvosapa.pdfIn PDF document text
    • https://mibonujatupogu.weebly.com/uploads/1/3/5/2/135297119/rorinarafigovijonine.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4370987/normal_5fd12a5b120b0.pdfIn PDF document text
    • http://taxutipepavij.iblogger.org/private_browser_pro_apk.pdfIn PDF document text
    • http://digtalcaliper09.xyz/24892627084k0jax.pdfIn PDF document text
    • https://gufonalika.weebly.com/uploads/1/3/4/0/134096228/865d060bd7.pdfIn PDF document text
    • https://lezevonunibo.weebly.com/uploads/1/3/4/5/134577944/d1134c.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4379719/normal_6009f4b3a69c3.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4528260/normal_5ff3816517f25.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://batuzotunar.rf.gd/eradication_of_h_pylori_guidelines.pdfIn PDF document text
    • https://s3.amazonaws.com/dutimajizowa/free_ux_case_study_template.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_off0000d260.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD260 5508 bytes
SHA-256: d13f1b6bf4068653ee802e445f6b53748a57c5b67b5b3843aa2cf7f8dcbebc55
font_01_sfnt_off0000e509.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE509 10716 bytes
SHA-256: 6cf05a5c7cc725ea615c5e59712928e5018f7d4fa941a9948bb3df8f9ff75476

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