Malicious PDF — malware analysis report

Static analysis result for SHA-256 cdb40d55c1391f85…

MALICIOUS

PDF

71.3 KB Created: 2021-09-08 15:48:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: f0cfaae8323a3f2e466120e0a8c5cbb2 SHA-1: e1e86d2b255679d4ccb6df82e680c944e99c7205 SHA-256: cdb40d55c1391f857c17fe1440ee87b083b415dba5d241c4714589a7e0a558d5
156 Risk Score

Malware Insights

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

The file was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier, indicating malicious intent. It contains numerous links, many pointing to compromised websites or disposable hosting, suggesting a link farm used for phishing or malware distribution. The presence of external URIs and compromised CMS upload links further supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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
  • 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://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1613746446a9f9---31377840350.pdf In PDF document text
    • https://cardolf.ro/files/xudimeralep.pdfIn PDF document text
    • https://buddingheights.org/wp-content/plugins/formcraft/file-upload/server/content/files/16131859444207---fopok.pdfIn PDF document text
    • https://alcc.c-zentrix.com/ALCC/mail_attachments/multitenant-ws-01/1/1630714400.pdfIn PDF document text
    • http://unseretochter.com/images/file/lutaxenafetil.pdfIn PDF document text
    • http://ckudzcssffhhj.handysociality.com/upload/files/78937509911.pdfIn PDF document text
    • https://bi-kiesabbau.de/cmsimple/images/file/84708784403.pdfIn PDF document text
    • http://herodumpsterrental.com/wp-content/plugins/super-forms/uploads/php/files/e87dcfb2d2f4c4cbdd1d89896350ddbe/revoxuruxabeninaxuse.pdfIn PDF document text
    • https://www.gml.de/wp-content/plugins/formcraft/file-upload/server/content/files/161382918485e4---90614232672.pdfIn PDF document text
    • http://group-anons.ru/userfiles/files/18462879926.pdfIn PDF document text
    • https://thesmithgrouphouston.com/wp-content/plugins/super-forms/uploads/php/files/172e4c3210158fe0472e200dc7c757d7/75874869435.pdfIn PDF document text
    • http://trungnguyenjsc.vn/uploads/image/files/nexanovifedunu.pdfIn PDF document text
    • http://pandoraecza.com/genelresimler/file/resujexetibenaf.pdfIn PDF document text
    • https://kaplaitalia.it/userfiles/files/90016365431.pdfIn PDF document text
    • http://xn----otbbfbbknchz.xn--p1ai/sadm_files/33251783069.pdfIn PDF document text
    • https://xn--22ck6bdp5cach0mc23a.com/ckfinder/userfiles/files/27530479810.pdfIn PDF document text
    • http://bjerkelunden.org/content/files/userfiles/file///xovevitumadutisogoduv.pdfIn PDF document text
    • https://economiadecomunion.net/ckfinder/userfiles/files/saroxagirazagezonon.pdfIn PDF document text
    • https://profession-your-dr.com/uploads/files/202109011105159765.pdfIn PDF document text
    • http://clinivetmadonnadirosa.eu/userfiles/files/jawagemeke.pdfIn PDF document text
    • https://arbormaster.net/uploads/files/69152598759.pdfIn PDF document text
    • http://net-work.cz/data/file/naxufozarikulubafi.pdfIn PDF document text
    • https://drhuanghair.com/uploads/files/202109022315427562.pdfIn PDF document text
    • http://oawebserver.com/piceditor/file/febeli.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=presentation+zen+garr+reynolds+pdf+downloadPDF 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_off0000b57b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB57B 15928 bytes
SHA-256: 22e86c2f00ddb46fd0ecea3aa6097ce922ab3373699eca05ba04ee076267e84e
font_01_sfnt_off0000de19.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE19 10932 bytes
SHA-256: 6fa5f5e5b69e49c010987ae2b819c068108651aa5e8169612992f0d43055509e
font_02_sfnt_off0000f77f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF77F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1