Malicious PDF — malware analysis report

Static analysis result for SHA-256 388d4f3c4a4f7500…

MALICIOUS

PDF

76.4 KB Created: 2021-04-12 19:38:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-28
MD5: 8d33773111042dc1b34f00d9bca06dfb SHA-1: 5f29be8541436d66d3697575844e21598344167f SHA-256: 388d4f3c4a4f7500cd3edd9bf99592b464b2458ccc8a06daa3c15b8055c5f4f3
126 Risk Score

Malware Insights

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

The PDF file was flagged as malicious by a machine learning classifier and ClamAV, indicating a high likelihood of malicious intent. The presence of numerous embedded URLs, many pointing to unknown or potentially malicious domains, suggests a link farm or phishing lure. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and a date, hinting at its construction. No scripts were extracted, but the PDF structure itself is indicative of a malicious document.

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 https://www.ofalloncasting.com/sites/default/files/webform/geguridafaj.pdf In PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/jonalizavilivoduse.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/topevonizudurazot.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/46846662681.pdfIn PDF document text
    • http://seiary.com/sites/default/files/webform/rec/jizexatunurometubukos.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/jokefogebefuzifuzew.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/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=how+to+install+parking+brake+bypassPDF link annotation
    • https://ubmemeaensoprod.s3.amazonaws.com/ifsec_international/call_for_papers/2021/03/52983615418.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/vabomabexajamoja.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/61493424170.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/16616798570.pdfIn PDF document text
    • https://www.vub.be/sites/vub/files/webform/lijulur.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_off0000def1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEF1 5136 bytes
SHA-256: ffa1d7f39ed16d752f6a20a871d7757787ff1a2f0d0de0d0a0f86e9763a3864a
font_01_sfnt_off0000f080.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF080 11684 bytes
SHA-256: 90e88cd35246a6b0f36ac884b70bc2ade43adac414a3ed1f35af98c363ab7a98
font_02_sfnt_off00011725.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11725 4324 bytes
SHA-256: 4fcfa7c68d76e23b667942a3ac892d2d5d88346478daafc61479ad4df4af3dd3

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