Malicious PDF — malware analysis report

Static analysis result for SHA-256 b63ecdf1feb88ace…

MALICIOUS

PDF

75.0 KB Created: 2021-04-14 11:32:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: bd06380f4c5fcc32f3f50bf30e2c3366 SHA-1: 953097a6ccb2f4134356b082b74de96ca9f44a4e SHA-256: b63ecdf1feb88ace396be51b31b7d5ede77afa0a87dd87af4fa32735b76d3e21
146 Risk Score

Malware Insights

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

The PDF file exhibits characteristics of a malicious document, including malformed streams and ML classifier flagging. It contains numerous embedded URLs, many pointing to seemingly legitimate domains but used in a link farm pattern, suggesting an attempt to obscure malicious destinations or distribute phishing content. The ClamAV detection as 'Pdf.Phishing.Trojan' further supports its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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.enwidth.com/sites/default/files/webform/resumes/79062027218.pdf In PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/38780162719.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/17184396690.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/vinoku.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/36138637258.pdfIn PDF document text
    • https://web.liderpapel.com/sites/default/files/webform/53484808665.pdfIn PDF document text
    • http://www.sumnercountyhospital.org/sites/default/files/webform/zupusozuxabodes.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/sovurusogizafubeb.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/bunovodedodasu.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/tasuwagorefovufozibojer.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/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=sinar+digital+back+23PDF link annotation
    • https://campusrec.princeton.edu/system/files/webform/18758627140.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/20850651402.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/zotatati.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/18848190838.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_off0000e676.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE676 5532 bytes
SHA-256: e3bec7ba9422a4f1767297cc22e0215106b72517633b5b8d60f3c54a4875687e
font_01_sfnt_off0000f95a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF95A 10880 bytes
SHA-256: 8fdb367b65fc1c4b49214c4d20c36079b638988e7f683a8c3fb4d0f9fe843221

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