Malicious PDF — malware analysis report

Static analysis result for SHA-256 a51764133ad1f446…

MALICIOUS

PDF

77.0 KB Created: 2021-06-14 18:50:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-14
MD5: 28d98b3a9a5743069bb3d84bc414b0bf SHA-1: 152a0775e057b873bfe6ee1cb8c4615d519ea6ad SHA-256: a51764133ad1f44694f774caa8f3cd465e3a66562386a20dad49ac0247b58dc8
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, specifically identified as a phishing trojan by ClamAV. It contains numerous links to external websites, many of which are hosted on compromised WordPress installations or disposable domains, suggesting a link farm designed to redirect users to malicious content. The embedded document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and a date, indicating it was likely generated programmatically to serve as a lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://laborke.ru/uplcv?utm_term=rap+music+unblocked PDF link annotation
    • https://nceptionsolutions.com/wp-content/plugins/super-forms/uploads/php/files/eb43a24ddfed24fa0e46cdf184086f85/salipusejo.pdfIn PDF document text
    • https://floridaholidayplanner.com/wp-content/plugins/super-forms/uploads/php/files/2e0492409da24a92d2a5c5fdc3bc13cf/rafitefojemo.pdfIn PDF document text
    • https://iamluno.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b7450180610---78178487832.pdfIn PDF document text
    • https://frasertechno.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a87550d4ea---1536467897.pdfIn PDF document text
    • http://chagatea.ru/wp-content/plugins/super-forms/uploads/php/files/02a81c6efb186a3f20199b212c914c09/53382005400.pdfIn PDF document text
    • http://irths.com/upload_files/files/34217897237.pdfIn PDF document text
    • http://thefutureofgolf.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1608b58c93f7a7---9570497577.pdfIn PDF document text
    • https://feriaesotericadeatocha.com/wp-content/plugins/formcraft/file-upload/server/content/files/160acabee07fa9---tosufasa.pdfIn PDF document text
    • http://ecbpolska.pl/wp-content/plugins/super-forms/uploads/php/files/b855ba7113e1fb70455a57e08cda5a7a/30582979159.pdfIn PDF document text
    • http://cuacongtrinh.vn/upload/files/68059706729.pdfIn PDF document text
    • http://zwickerfoto.hu/_user/file/85677996818.pdfIn PDF document text
    • http://traditionsradio.com/wp-content/plugins/super-forms/uploads/php/files/k1io0veg3afe9c6htj0el1m522/10397602105.pdfIn PDF document text
    • http://2016montemayorreunion.com/clients/e/e5/e530e98a7ee505477716bae2fe71cdef/File/57679973431.pdfIn PDF document text
    • http://madmojo.com/fckupload/file/zasejojidumogim.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e252.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE252 5332 bytes
SHA-256: 2061202743bbb3ac7a1662de9779e02f81053276e5611221ef6d3309d7eaebec
font_01_sfnt_off0000f458.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF458 1984 bytes
SHA-256: d975ee5ed68b3f456069e2400a3f3454167992d211219adf3a5ab92225d52a38
font_02_sfnt_off0000fdcb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDCB 11772 bytes
SHA-256: 1f59207ac262839b3c749a60f4c04fdb7ecfd28eabc28ab81371fef8cb46b088