Malicious PDF — malware analysis report

Static analysis result for SHA-256 c43937b655652151…

MALICIOUS

PDF

76.2 KB Created: 2021-04-18 16:29:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: b8802bb8e82be4cd6d69b208c2035907 SHA-1: 461dd96de714067449ee340980891bd39f2ad334 SHA-256: c43937b655652151df669b331abf3aab78f2cefd845db973b85992af7178a8f6
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, indicating a high likelihood of malicious intent. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' suggests the document is designed as a link farm, pointing to numerous distinct hosts, likely to obscure malicious destinations. While no executable scripts were extracted, the embedded URLs and the nature of the link farm heuristic strongly suggest an attempt to redirect users to malicious content, possibly for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://aboss.by/sites/default/files/webform/32639212941.pdf In PDF document text
    • https://www.uts.cw/sites/default/files/webform/nukuromenalifaru.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/todoxobolukajit.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/dufadurelabakugozuku.pdfIn PDF document text
    • https://www.woonsocketri.org/system/temporary/webform/danajon.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/38059385999.pdfIn PDF document text
    • https://www.termis.org/system/files/webform/67198091979.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/welukugipevodabarovefeweb.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/tinijozude.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/bedadijone.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/41850888982.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/61943826361.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/zuloliresu.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/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=al%2528h2o%25296+3%252B+hybridization+of+alPDF link annotation
    • https://campusrec.princeton.edu/system/files/webform/febapaxugodikuzakepob.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/vabomabexajamoja.pdfIn PDF document text
    • https://www.vub.be/sites/vub/files/webform/86005813007.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_off0000e874.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE874 5704 bytes
SHA-256: 0dfdf981ddd3c93ee0f35d2802d666ad34dff1f41c361281d71d9fe5347561f7
font_01_sfnt_off0000fbfd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBFD 11600 bytes
SHA-256: f120fd31fe6d645b8b5e9a80d7050ebc33be5d1a5adcd9c78ba2ed49840ff571

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