Malicious PDF — malware analysis report

Static analysis result for SHA-256 c22d495bcf72c0af…

MALICIOUS

PDF

91.8 KB Created: 2021-09-20 11:22:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 5a49a2f5b000942eb0c68363ed9a82b6 SHA-1: 4c638d34b4822a8c4809da470ffd82cf56c95311 SHA-256: c22d495bcf72c0afce6a9fe7a8069031128906f98c835ea40e3bc0e4878ea5af
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs, many of which point to other PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some URLs pointing to compromised CMS upload storage. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9902

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • 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://zd-zeta.com/uploads/files/202109152348242377.pdf In PDF document text
    • http://asupuro.com/user_data/image/file/40913438557.pdfIn PDF document text
    • http://chrisdepanneservices.fr/Sites/cds/files/97619642166.pdfIn PDF document text
    • https://ssvacancy.com/ckfinder/userfiles/files/nadesiwifedebifoso.pdfIn PDF document text
    • https://postelezmasivu-ostrava.cz/ckfinder/userfiles/files/99773242855.pdfIn PDF document text
    • https://www.opsclown.it/ckfinder/userfiles/files/152104053.pdfIn PDF document text
    • http://airfa.it/userfiles/file/81990441367.pdfIn PDF document text
    • http://xfswchem.com/upload/files/jatofoxijemuludanep.pdfIn PDF document text
    • http://cdkuys.handysociality.com/upload/files/lelebezisifimekatawabefej.pdfIn PDF document text
    • http://huerural.com/uploads/image/files/39512238836.pdfIn PDF document text
    • http://kengosushionlineorder.com/uploads/files/59000639283.pdfIn PDF document text
    • http://luyenthidhcanhsat.com/Images_upload/files/52969491339.pdfIn PDF document text
    • http://viaterrestre.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613e1daed95d2---71882383280.pdfIn PDF document text
    • http://www.pro9apps.com/app/webroot/files/uploadimagesfile/66611543755.pdfIn PDF document text
    • https://www.golddustdental.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137a8fb9975b---35250093203.pdfIn PDF document text
    • http://cmuniontravel.com/userfiles/file/6597839456.pdfIn PDF document text
    • http://eng.sut.ac.th/tce/2016/administrator/ckfinder/userfiles/files/fizijanadojejezokuxa.pdfIn PDF document text
    • https://www.allterra.group/wp-content/plugins/super-forms/uploads/php/files/8a43648c78ca62e45beb3f2e1707dc6c/71701226379.pdfIn PDF document text
    • http://magnumprint.ru/upload/files/tisotizugokofawomux.pdfIn PDF document text
    • http://elandtour.com/FileData/ckfinder/files/20210911_FEE480CAE3343399.pdfIn PDF document text
    • http://gddfboiler.com/uploads/files/77833824477.pdfIn PDF document text
    • http://zanethompson.com/userfiles/file/xudapaxixupupiwibugowakuw.pdfIn PDF document text
    • http://okmarin.ru/userfiles/file/92427156038.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=me+after+you+pdfPDF 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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d1c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1C9 1680 bytes
SHA-256: 6c08887b596ecb472c5a0482df8c2f828d83fc5b5d16111ed0caa1fced1b35dc
font_01_sfnt_off0000d9c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9C1 24476 bytes
SHA-256: 057bf1fa3a4691da59f919a09b209a90d4b3f5d6b02bc60dad5c2391cd77b7fa
font_02_sfnt_off00011820.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11820 10288 bytes
SHA-256: 4c3fc19466b0158c54523e54846e7abdf037cd734188e3432cb2e987355e49a4
font_03_sfnt_off00012f6d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12F6D 17088 bytes
SHA-256: 48e91e5a89aaf1fc5c2ec6a4c168c13003c796f000f273b351a6efba64c8e36e
font_04_sfnt_off000148a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x148A0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1