Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8e5451312b83766…

MALICIOUS

PDF

103.0 KB Created: 2021-09-15 15:24:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: cfcb540a5164c9c9882f46203e1c7299 SHA-1: 2deb95829f376c8c27272d7ec985c2860aefdf27 SHA-256: b8e5451312b83766c36e1607c72c0d1cc4ce9d3d3b6f05c464013c9c59d40964
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous external links, many pointing to disposable hosting or compromised CMS uploads, indicating a link farm or phishing lure. The ML classifier and ClamAV detection strongly suggest malicious intent. The embedded JavaScript likely facilitates the redirection to these external URLs, which are the primary IOCs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9904

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://archism.ru/uplcv?utm_term=watch+golf+online+free
    • https://nsck-cykelmotion.dk/userfiles/file/vafadofonezomasepikuraxe.pdf
    • http://teusz.pl/UserFiles/file/9850318790.pdf
    • https://vinadesigndanang.vn/uploads/image/files/7904160344.pdf
    • http://theleadershipworks.com/PO2/UPFILE/userfiles/files/sefub.pdf
    • http://studiocinti.eu/userfiles/files/supexu.pdf
    • http://cpbnatation.fr/fckeditor/userfiles/file/65481428032.pdf
    • http://mfplus.ba/wp-content/plugins/formcraft/file-upload/server/content/files/16135b9fa9f84d---40521125411.pdf
    • http://soleilboo.com/images/uploads/files/20029923368.pdf
    • https://phuketwebstudio.com/ckfinder/userfiles/files/puxezokoguzegipa.pdf
    • http://kimsanghun.com/upload/userfiles/file/202198159149774.pdf
    • http://anpo.vn/upload/files/sikanojagitotufexomajazi.pdf
    • http://photou.cc/ckfinder/userfiles/files/22917686873.pdf
    • https://papiratisk.cz/soubory/bufimefizoretijerunititu.pdf
    • https://popa.com.br/wp-content/plugins/super-forms/uploads/php/files/6343b21bfd5ff52daacbc8b882aa155e/83752490628.pdf
    • http://xn--or3bo5mvlb.com/data/editor/file/35941807555.pdf
    • http://slavutich-media.ru/userfiles/file/zudipopezodavisudaf.pdf
    • https://ryokanclub.com/FileData/ckfinder/files/20210904_66D34024E33ED15D.pdf
    • http://www.cpnatacao.pt/backoffice/ckfinder/userfiles/files/mewebu.pdf
    • http://backupcenters.com/userfiles/file/tinefuzaxuv.pdf
    • http://jrpst.pl/userfiles/file/jexunoputogoludozirifupaf.pdf
    • http://hokkaido-love87.com/app/webroot/js/ckfinder/userfiles/files/85010806336.pdf
    • http://wienbildarchiv.com/upload_files/files/jipanekudatelowarejo.pdf
    • http://favorit.pl/userfiles/file/tajag.pdf
    • https://www.davidcosz.de/wp-content/plugins/super-forms/uploads/php/files/mokfeh0v4gs16jqp5npm47r83e/87274063422.pdf
    • http://zpkprzemysl.pl/ckfinder/userfiles/files/varozajewamegabelokapab.pdf
    • http://cegled.varosom.hu/userfiles/files/95051855649.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012ef4.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12EF4 16792 bytes
font_01_sfnt_off0001470b.bin
1ff36a9ed8a99d32b7437bf38649349e7cc06c549a02d8f07c82f171651e5595
pdf-font-stream PDF embedded font (sfnt) at offset 0x1470B 10440 bytes
font_02_sfnt_off00015eb4.bin
b047e182c0cfff9c0fcdff5496bbe13ca1cebbc4ccc5ab633d1fe81572930f61
pdf-font-stream PDF embedded font (sfnt) at offset 0x15EB4 18232 bytes