Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8a51b8824ac42b5…

MALICIOUS

PDF

69.6 KB Created: 2021-04-25 11:58:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 5363d86d42c35d2593c45def51df8b09 SHA-1: ffa2e093a4ae9929b7b3acdd016f7eefa25c0196 SHA-256: c8a51b8824ac42b58e89ed2753035e2c2061bf35c7d0b0866f7f4fc7c7ab80a8
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. It contains numerous embedded URLs, many of which point to potentially compromised legitimate websites or disposable domains, suggesting an attempt to redirect users to malicious content. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports a phishing or spamming campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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 https://www.newburghgroup.com/sites/default/files/webform/resumes/41319995155.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/11364316539.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/nukuromenalifaru.pdfIn PDF document text
    • https://natsihwa.org.au/sites/default/files/webform/degajakuko.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/woluweweketasuzizolog.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/84972388600.pdfIn PDF document text
    • https://www.afscme65.org/system/files/webform/rerezuduzolorefa.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/A3Ryygt5BCM/uplcv?utm_term=river+runs+through+it+movie+quotesPDF link annotation
    • https://lib.asu.edu/system/files/webform/simadovi.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/7842358922.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/fapivo.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/95830943344.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_off0000d5ed.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5ED 5048 bytes
SHA-256: 4c4398782125709a4665ca68e675d1c4a89879701a3582254d6fa048ceec032b
font_01_sfnt_off0000e6fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6FD 10220 bytes
SHA-256: 572acc77fccfd48a866bbae177b8ffc8362cb7c06d59f6e2b934427b184b3323

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