Malicious PDF — malware analysis report

Static analysis result for SHA-256 c9a3c840027f49e9…

MALICIOUS

PDF

76.7 KB Created: 2021-04-19 17:56:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 144e415e88b1ead0a5ea745f6c7ec193 SHA-1: d4f9b455b51ba93f457b0fe6e4344a5f8f415f42 SHA-256: c9a3c840027f49e94e8a09b3263a23d3b7e64cff79ae45d3328e5d32eb0c37ac
126 Risk Score

Malware Insights

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

The file is a PDF document that exhibits characteristics of a phishing or malware distribution lure, as indicated by the ML classifier and ClamAV detection. The document body, though heavily obfuscated, suggests a lure related to educational materials. The presence of numerous embedded URLs, many pointing to potentially compromised or disposable domains, strongly suggests an attempt to redirect users to malicious sites. While no scripts were explicitly extracted, the PDF format can embed JavaScript for malicious actions, and the heuristic PDF_SEO_DISPOSABLE_LINK_FARM points to a link farm strategy.

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://ambrose.edu/sites/default/files/webform/durigoxilakomisi.pdf In PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/24974410021.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/80098342864.pdfIn PDF document text
    • http://portal-mysigma.com/system/files/student-proof/pifudolaloxafedotodela.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/20598750849.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/41345860665.pdfIn PDF document text
    • https://www.woonsocketri.org/system/temporary/webform/mupiroto.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/65047245793.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/85881129832.pdfIn PDF document text
    • https://aboss.by/sites/default/files/webform/tatesejozamelifat.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/604022749.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/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=maths+book+class+7PDF link annotation
    • https://www.vub.be/sites/vub/files/webform/16824703900.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/20850651402.pdfIn PDF document text
    • https://www.vub.be/sites/vub/files/webform/pagilavamuvawasaxega.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_off0000f145.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF145 5080 bytes
SHA-256: e21a1852c292f1525770002ef3f9e1b8d65478e71897293f005833d07ec23c60
font_01_sfnt_off000102a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102A4 10492 bytes
SHA-256: 59275ae4b7360183e67373d325a3f4b429343b12f10a9b60552f70563a123bcc

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