Malicious PDF — malware analysis report

Static analysis result for SHA-256 f9c118407baae053…

MALICIOUS

PDF

73.9 KB Created: 2021-04-11 13:01:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: f58386c0248ddcd351b2c225c0188ce6 SHA-1: 03b6b115e5df103a12dcc59acf6095439402ea22 SHA-256: f9c118407baae053d56c8f77777aca7351f8528d996a72c30257ff0824d75f36
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 are hosted on seemingly legitimate domains but are part of a link farm designed to obscure the true destination. The document body, though heavily obfuscated, suggests a lure related to educational exercises, which is a common tactic for phishing or malware delivery. No scripts were extracted, but the presence of multiple external URIs and the overall structure indicate a likely attempt to redirect the user to a malicious site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

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://web.liderpapel.com/sites/default/files/webform/53484808665.pdf In PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/zolevijovexoneda.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/paxifufal.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/61928937085.pdfIn PDF document text
    • https://www.afscme65.org/system/files/webform/96479551545.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/68038126183.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/25507329945.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/68138040624.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/jitebetususi.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/vopezupudatirarib.pdfIn PDF document text
    • http://russian-ice-spb.ru/sites/default/files/webform/files/77599308563.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/27804174203.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/~3/3vuEKuznOb8/uplcv?utm_term=ejercicios+de+palabras+agudas+graves+esdrujulas+y+sobreesdrujulas+para+imprimirPDF link annotation
    • https://campusrec.princeton.edu/system/files/webform/34970544405.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/16616798570.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/wijudabopijobomoxusosul.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/vujipudujusikal.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_off0000de08.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE08 5728 bytes
SHA-256: 6287d7417541903c26905fdd3122672c8ed11551df969002a3859b5a3717cce3
font_01_sfnt_off0000f185.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF185 11864 bytes
SHA-256: f668763b45847056ea6cf584a7e8746ad2a53bbd73ae9434cca3f7a4727a5957

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