Malicious PDF — malware analysis report

Static analysis result for SHA-256 a40f67444360e45a…

MALICIOUS

PDF

70.6 KB Created: 2021-04-14 23:56:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: b9f45a9719560b95d2209ad2a7066642 SHA-1: 2d453936a27fcd9152462fe7501073baf09b85c9 SHA-256: a40f67444360e45a8c0329d32aed457d896c1357b82434f1a362e43e88cafa7a
126 Risk Score

Malware Insights

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

The sample was identified as malicious by ML classifiers and ClamAV, with a critical heuristic firing for 'Pdf.Phishing.Trojan'. It contains numerous embedded URLs, many pointing to university or organizational domains, but some are hosted on unknown or potentially disposable domains, suggesting a link farm for phishing. The PDF structure and embedded content indicate it's designed to lure users into clicking malicious links, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 http://cicatsalud.com/html/sites/default/files/webform/foxegedukob.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/85138354947.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/42535902170.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/3242210986.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/35757612566.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/71926652616.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/zuguxinukebezukul.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/lolavojirubopikumu.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/nunemoxajusadokuxilebe.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/xugapovapoz.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=d%2526d+player%2527s+handbook+5e+amazonPDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/85064040694.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/sikukuditizituxabisezopel.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/36479690150.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/nexeginexepor.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/wosevojowavinojefe.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/posilo.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cfb4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCFB4 3484 bytes
SHA-256: aabf92024a63f9a88d7671bdc9e7ad9bdd48a300d718d9b182b35c5616f8c0c3
font_01_sfnt_off0000db21.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB21 10996 bytes
SHA-256: 95fa6420e001d1faf98723a9d9d54748ce9cc491f0e6c9fc487052ed821842a5
font_02_sfnt_off00010006.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10006 4324 bytes
SHA-256: ff5f0ef16caf3e97cd1984b3a03ea88e11eab8cf63d2ee006085a4b9995833f3

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