Malicious PDF — malware analysis report

Static analysis result for SHA-256 671e9dd77e076f91…

MALICIOUS

PDF

75.4 KB Created: 2021-09-15 16:24:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 34b6b54d535fe49ed82555be767b1440 SHA-1: e9c97db7bbf68a9ee47c2c64a397683de2224589 SHA-256: 671e9dd77e076f915bb07bc70191e911f83e6970a06c5e545219cfdfae587c98
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, containing numerous embedded URLs pointing to external PDF files. The document body is heavily obfuscated and unreadable, suggesting an attempt to hide its malicious intent. The primary attack pattern involves tricking users into clicking links that lead to further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://bitree.net/ckfinder/userfiles/files/misexutokud.pdf In PDF document text
    • http://bajcsidavidfoto.com/_user/file/faroto.pdfIn PDF document text
    • http://salonorganica.ru/upload/files/17149643835.pdfIn PDF document text
    • https://alistairmills.com/ckfinder/userfiles/files/wunobag.pdfIn PDF document text
    • https://ist-lb1.istanajp.com/contents/files/56224558714.pdfIn PDF document text
    • https://kfmaccounting.com/webroot/img/content/files/35578915651.pdfIn PDF document text
    • http://asclyziarskyklub.sk/userfiles/file/xaserizuxufizuge.pdfIn PDF document text
    • https://stefandes.com/wp-content/plugins/formcraft/file-upload/server/content/files/161410bfbb9fcb---zunalaxojolaworegokuru.pdfIn PDF document text
    • https://alternatifhirdavat.com/upload/ckfinder/files/pukore.pdfIn PDF document text
    • http://humidorio.de/ckfinder/userfiles/files/83569526577.pdfIn PDF document text
    • https://colakcivi.com/userfiles/file/4313980309.pdfIn PDF document text
    • https://tspinstruments.com/cache/fck_files/file/86159116339.pdfIn PDF document text
    • http://snieznik.pl/userfiles/file/54088724364.pdfIn PDF document text
    • http://ctyrkolky-gamax.cz/data/dokumenty/20086116093.pdfIn PDF document text
    • http://makaroma.fr/upload/file/35327535546.pdfIn PDF document text
    • http://sosnovgeo.ru/userfiles/file/40401919946.pdfIn PDF document text
    • https://coherence.cz/userfiles/file/31238413575.pdfIn PDF document text
    • http://columb-sklep.pl/userfiles/file/xaxukuribufesiridivusated.pdfIn PDF document text
    • http://tpfish.com.taipei/archive/upload/files/fojonegabubol.pdfIn PDF document text
    • http://minisadik-margaritka.ru/admin/ckfinder/userfiles/files/rudumig.pdfIn PDF document text
    • https://kocarbonag.com/luutru/files/fifove.pdfIn PDF document text
    • http://tinavaron.com/ckfinder/userfiles/files/89528718192.pdfIn PDF document text
    • http://giaydantuongphongngudep.com/images/news/file/tevipida.pdfIn PDF document text
    • http://dijladentalcenter-qa.com/userfiles/file/83989461137.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=android+discover+devices+on+wifi+networkPDF link annotation
    • 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_off0000c4a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC4A7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000dcb9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCB9 16640 bytes
SHA-256: f0338009957dbaddf9b8b1b43fe3107f313240da976e818a85a57312d8d770ce
font_02_sfnt_off000107bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107BB 10488 bytes
SHA-256: 6508c7a658d036deef3c41fec34c712390907cb310f0cc6ca25357cc308bd56d