Malicious PDF — malware analysis report

Static analysis result for SHA-256 71672635eb232670…

MALICIOUS

PDF

70.5 KB Created: 2021-04-21 11:32:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 31052a20f788fc9f406cbf7202674aae SHA-1: 7c0ef20d6229510ce380e26aece17ef6fc7311c1 SHA-256: 71672635eb23267030f4e37a1fdb8c9c64433f03d0e18d3c663dd23b21ef7044
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which are hosted on seemingly legitimate domains but point to suspicious PDF files. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. Although no scripts were explicitly extracted, the heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' suggests a tactic to obscure malicious links within a large number of seemingly unrelated URLs.

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 https://www.natsihwa.org.au/sites/default/files/webform/xugapovapoz.pdf In PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/dekif.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/99544266771.pdfIn PDF document text
    • https://architecturaldesigninc.com/sites/default/files/vudezuluxi.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/30199048500.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/27999686052.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/dutaberapowuniz.pdfIn PDF document text
    • https://aboss.by/sites/default/files/webform/tatesejozamelifat.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/95147346690.pdfIn PDF document text
    • http://www.sumnercountyhospital.org/sites/default/files/webform/72664382884.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/65047245793.pdfIn PDF document text
    • https://www.afscme65.org/system/files/webform/fabituwinuxofi.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/PmAiG5ZyT-k/uplcv?utm_term=casio+pro+trek+pag240b-2+pathfinderPDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/67925993666.pdfIn PDF document text
    • https://gradfutures.princeton.edu/system/files/webform/25860956451.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/libovonudipiguriteg.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/luzatebinibaxopititum.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/liwubuwivak.pdfIn PDF document text
    • https://www.vub.be/sites/vub/files/webform/pagilavamuvawasaxega.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/31460711967.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_off0000d213.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD213 5772 bytes
SHA-256: 333afa48fe624f9195e86502f0d9e546e681e28951a9748a0be8851a18ab38e4
font_01_sfnt_off0000e5be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5BE 12200 bytes
SHA-256: 2b497483e36503f8302da48d930fb9c00ca34c5ad8ff7948f89c6eec05626e12

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