Malicious PDF — malware analysis report

Static analysis result for SHA-256 821c9c61f98bd73b…

MALICIOUS

PDF

77.3 KB Created: 2021-09-15 17:31:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: d3f0f10333f1a97c29ce020db480eb34 SHA-1: 2fb9d57235c1055755384db785acc51220dcdc24 SHA-256: 821c9c61f98bd73bca8b1fd87544c186483fde9c22506126ada56fdfeb61f46d
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The presence of an embedded JavaScript stream (T1059.007) and numerous external URIs, many of which point to unknown or potentially disposable domains, suggests a phishing or credential harvesting attempt, likely delivered as a spearphishing attachment (T1566.001). The PDF structure and numerous links are indicative of a link farm designed to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 6

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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.jakketoes.be/ckfinder/userfiles/files/53265661801.pdf In PDF document text
    • https://watertorens.nl/userfiles/file/33245222705.pdfIn PDF document text
    • http://80tner.netsociality.com/upload/files/19647596025.pdfIn PDF document text
    • http://www.martiusstaden.org.br/js/ckfinder/userfiles/files/nupupepiruje.pdfIn PDF document text
    • https://asfus.net/virgsurv/userfiles/file/1780728253.pdfIn PDF document text
    • http://keifo.ru/ckfinder/userfiles/files/87059013177.pdfIn PDF document text
    • https://hps-gruppe.com/wp-content/plugins/super-forms/uploads/php/files/b2f8v5ru9f1e6h2klccpf4a5lm/limuvigumupebujaxido.pdfIn PDF document text
    • https://coverline.ro/userfiles/file/91377250969.pdfIn PDF document text
    • https://kaptenhoki.net/contents/files/zibutusegavatepidexememe.pdfIn PDF document text
    • http://vasvaripalmuzeum.hu/upload/file/23145418720.pdfIn PDF document text
    • http://custom-mugs-factory.com/uploadfile/files/joralerimopozuwanubibi.pdfIn PDF document text
    • https://x-software.cz/data/file/gofawadu.pdfIn PDF document text
    • http://ansonseatery.com/uploads/files/2478511.pdfIn PDF document text
    • https://navoloki.mebel18.com/uploads/files/zumukigogolaxesalidi.pdfIn PDF document text
    • http://househouse.it/userfiles/files/sewodenunewesede.pdfIn PDF document text
    • http://cgt-fo-csc.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16135bee7b4c92---74030360325.pdfIn PDF document text
    • https://tenfci.org/userfiles/file/3027792610.pdfIn PDF document text
    • http://kristiankutschera.de/userfiles/file/kibupazetuxedavikakirow.pdfIn PDF document text
    • http://www.c-l-r-p.com/admin/ckfinder/userfiles/files/51497082462.pdfIn PDF document text
    • http://teraval.cz/res/file/nenikip.pdfIn PDF document text
    • http://gezond-trakteren.nl/kasteel-doornenburg-img/bestandenfile/64588320750.pdfIn PDF document text
    • https://varbackaforskola.se/ckfinder/userfiles/files/nider.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=heterocyclic+chemistry+problems+and+solutionsPDF link annotation
    • https://www.assessment.unibe.ch/app/webroot/js/ckfinder/userfiles/files/23815863976.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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c93c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC93C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e153.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE153 11124 bytes
SHA-256: 8479c8777bb88f1b3a932329a76de72a46074fde97ea0629be85a569105fe8ed
font_02_sfnt_off0000fadb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFADB 17240 bytes
SHA-256: 35c500feb60f0ece33cfe7e7312da4c7debfb31aede8998014c9c3904cb08bbe