Malicious PDF — malware analysis report

Static analysis result for SHA-256 a85f1571bb6f7ffe…

MALICIOUS

PDF

71.3 KB Created: 2021-04-10 16:47:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-28
MD5: b2bad6e1d069a0fc570411011460e23a SHA-1: f5b9aa6941de1de428e22e33fb0df8f127169148 SHA-256: a85f1571bb6f7ffeb3e1cbbe091de12c4b412a5ea2be584c0b8c3a404d952473
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to potentially malicious or unknown domains. While the document body is heavily obfuscated, the presence of multiple external URIs and the link farm heuristic strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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 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://www.pbttphtk.gov.my/sites/default/files/webform/nolukaronedibikix.pdf In PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/2923424149.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/kupoxogij.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/44437875789.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/16831560309.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=all+bollywood+songs+320kbps+freePDF link annotation
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/46273532178.pdfIn PDF document text
    • https://gradfutures.princeton.edu/system/files/webform/25860956451.pdfIn PDF document text
    • https://umatter.princeton.edu/system/files/webform/requests/72435273025.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/jelozubunumi.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/68272747422.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/98562832035.pdfIn PDF document text
    • https://ubmemeaensoprod.s3.amazonaws.com/ifsec_international/call_for_papers/2021/03/gijewosatesozug.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/mizol.pdfIn PDF document text
    • https://www.vub.be/sites/vub/files/webform/ludazerubadariwevulefaxu.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_off0000d93b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD93B 5824 bytes
SHA-256: e35158da92e195bc1348454c4b81c80b1784a41ff8a85104a82df3c1fa132fd3
font_01_sfnt_off0000ed3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED3B 10304 bytes
SHA-256: ce47b021dc8809fbb70a0a33350e5ff3d851baac139959082445a7c8e1c75a2b

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