Malicious PDF — malware analysis report

Static analysis result for SHA-256 8532c6e10f7a3440…

MALICIOUS

PDF

71.7 KB Created: 2021-09-21 13:52:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 435dc366600fb80ae92dd56469a59e79 SHA-1: 53e937e3194d41e46a201b4ee7aba35d3f18af46 SHA-256: 8532c6e10f7a344076a38a110c7b4bfdf39468d9e02ae095ababb61c4de4ae66
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, one of which is `https://synerhu.ru/uplcv?utm_term=what+to+eat+for+breakfast+when+working+out`. The document body is heavily obfuscated, but the presence of embedded URLs and the link farm heuristic strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://synerhu.ru/uplcv?utm_term=what+to+eat+for+breakfast+when+working+out PDF link annotation
    • https://acethamessecurity.co.uk/wp-content/plugins/super-forms/uploads/php/files/3732f271053195d1d6dca1ad4f618e11/47221735617.pdfIn PDF document text
    • https://ntiverification.com/userfiles/file/12141200332.pdfIn PDF document text
    • http://contua.org/userfiles/file/fasifedagidiwugan.pdfIn PDF document text
    • http://inhome360.ru/admin/ckfinder/userfiles/files/bixaxerina.pdfIn PDF document text
    • https://newtech-utm.pl/userfiles/file/75685910027.pdfIn PDF document text
    • http://www.terresdescaraibes.fr/file/42681970397.pdfIn PDF document text
    • http://nattukoottam.com/userfiles/file/32592952604.pdfIn PDF document text
    • http://iburgisidimarsala.eu/userfiles/files/60600893326.pdfIn PDF document text
    • https://dptech.vn/uploads/files/lirugitipilavid.pdfIn PDF document text
    • http://golfproradost.cz/webpagebuilder/ckfinder/userfiles/files/90950915140.pdfIn PDF document text
    • http://sweed-trans.eu/ckfinder/userfiles/files/82047848187.pdfIn PDF document text
    • https://nutrishop.in/ci/userfiles/files/diwulomovegoferoxudurol.pdfIn PDF document text
    • https://clinicaabrahaoosta.com.br/ckfinder/userfiles/files/57917345673.pdfIn PDF document text
    • https://sreekanakananda.com/ckfinder/userfiles/files/neluwizepufarobuxegugeko.pdfIn PDF document text
    • https://thietkewebseo.com/webroot/img/files/54841848362.pdfIn PDF document text
    • http://www.eurosecurimed.com/ckfinder/userfiles/files/65157157595.pdfIn PDF document text
    • http://kisito.com/userfiles/file/kigevetofa.pdfIn PDF document text
    • https://global-brand.net/userfiles/files/losirunarikopel.pdfIn PDF document text
    • http://vinaktv.com/storage/ckfinder/files/satasaxeba.pdfIn PDF document text
    • https://shreegroupco.com/userfiles/file/najutap.pdfIn PDF document text
    • http://mariekevanvlierden.nl/survey/userfiles/files/vuvazoxukokaseku.pdfIn PDF document text
    • http://nuuts.mn/uploads/assets/misubagikizaguleni.pdfIn PDF document text
    • https://pikewallis.no/wp-content/plugins/formcraft/file-upload/server/content/files/161429c3c7de4b---43643322841.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_off0000b734.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB734 10860 bytes
SHA-256: 3dedab41cc72bbc1a773ed1205e4b91b3e4bdce63c4d853a8bf243dcc7c42603
font_01_sfnt_off0000d05a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD05A 16164 bytes
SHA-256: 173a03579868f6d29f4887ee99efaf81b63866b4b9f98a1bd68fedcdef40db96
font_02_sfnt_off0000f979.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF979 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1