Malicious PDF — malware analysis report

Static analysis result for SHA-256 b21c88d97ce14733…

MALICIOUS

PDF

171.6 KB Created: 2021-04-16 02:14:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 33d98c4e9d0ae8ac7fe85208b99a9805 SHA-1: 9e6f5c8a00d35c07e500f83ffead195ece937cef SHA-256: b21c88d97ce14733ce4847644c97d312d71b89b92c137748edc17de6c2ab816e
126 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a phishing or trojan payload. The document contains numerous embedded URLs, many of which point to seemingly legitimate domains but are likely part of a link farm designed to redirect users to malicious sites. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggests this is a tactic to obscure the final malicious destination. While no scripts were explicitly extracted, the nature of the PDF and the embedded URLs point towards a phishing attack vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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.uts.cw/sites/default/files/webform/nukuromenalifaru.pdf In PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/74795851198.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/balulata.pdfIn PDF document text
    • http://seiary.com/sites/default/files/webform/rec/pexutagizoniged.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/dovav.pdfIn PDF document text
    • https://web.liderpapel.com/sites/default/files/webform/dojoxopanikofogenag.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/sovurusogizafubeb.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/65810703597.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/tuwagamutavuvefofufeniz.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/15194676649.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/21073527915.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/jowodudarazobipadumalo.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/57515461030.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/55178968397.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/70645978292.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/22435641867.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/mimixinaxeralowevowijut.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/bugoxugokerudanetisene.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://fedorahosted.org/lohitIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=what+is+hindi+meaning+of+transcendental+meditationPDF link annotation
    • https://thesanfordschool.asu.edu/sites/default/files/webform/20850651402.pdfIn PDF document text
    • https://gradfutures.princeton.edu/system/files/webform/buviboxakutovovujigobimis.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_off000253a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x253A0 5448 bytes
SHA-256: 7b4609f369afa7ee5918656b78fa298cfb33ca68728f1bcade5cd2e057837344
font_01_sfnt_off0002660a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2660A 12768 bytes
SHA-256: b259c1edf7d21a2c221dc4d28924fe5a406e552492de5e27007396f221e0d4bb
font_02_sfnt_off00028fde.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x28FDE 3452 bytes
SHA-256: f6621a75d9b333936796bf07c595f2ee3354dd9c118453a1a9ac36896031ad60