Malicious PDF — malware analysis report

Static analysis result for SHA-256 691c766e40eff9ef…

MALICIOUS

PDF

77.0 KB Created: 2021-06-09 19:28:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-26
MD5: 2dd280eaf5200155ded6030e20fea3ff SHA-1: 8bc9c59d4d0d80fd8d3932756f05b164400b012f SHA-256: 691c766e40eff9ef7bca9d138f9839b9fc4077c54e946e144df27fca6c3fced4
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URIs and link farm heuristics pointing to compromised WordPress sites, suggesting it's used for SEO manipulation or to redirect users to malicious content. The document body is heavily obfuscated and contains metadata from wkhtmltopdf, but no executable scripts were extracted.

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://medvor.ru/uplcv?utm_term=volume+of+sphere+formula+using+diameter PDF link annotation
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f6cda5b428---naboxiluziwewaxuno.pdfIn PDF document text
    • https://akproauto.com/nbloom/fckuploads/file/54667287814.pdfIn PDF document text
    • https://robotics-institute.com/wp-content/plugins/super-forms/uploads/php/files/i36aq0r7k8a0m5cuo6oesqlg2m/52278345527.pdfIn PDF document text
    • https://www.northernillumination.com/wp-content/plugins/super-forms/uploads/php/files/fa85445d75dda388856b852f7f88a0ca/12838275104.pdfIn PDF document text
    • http://oreade-breche.fr/userfiles/file/59480873440.pdfIn PDF document text
    • https://ceadersvalet.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608853134693e---66815031446.pdfIn PDF document text
    • http://svenstavik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a11151ea22---19576452691.pdfIn PDF document text
    • http://jointrilogy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607509ae180f6---nemogetofivumelufi.pdfIn PDF document text
    • http://thedewakohchang.com/image/upload/File/ibalukemulivuguva.pdfIn PDF document text
    • https://dixietemporarystorage.com/wp-content/plugins/super-forms/uploads/php/files/c9c4b2a67f3ebf23fdb241117aa63b0d/35597114108.pdfIn PDF document text
    • http://bizwd.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094be32177b7---koniperujazuderabafirol.pdfIn PDF document text
    • http://www.empresasdelimpeza.info/wp-content/plugins/formcraft/file-upload/server/content/files/160bf87c4737d2---gisedaj.pdfIn PDF document text
    • https://investmentskillsgroup.com/images/userfiles/file/28716453459.pdfIn PDF document text
    • http://krindustria.com.br/site/wp-content/plugins/formcraft/file-upload/server/content/files/1606d8bb38835e---57693960418.pdfIn PDF document text
    • https://admonks.ru/wp-content/plugins/super-forms/uploads/php/files/63b6b5a2d6c54e992e942efa4f241e40/gesulofikog.pdfIn PDF document text
    • https://senhewood.com/d/files/78087656765.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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ebe1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBE1 5420 bytes
SHA-256: cc63370e66a2e4e3251903710585491bbf9f1cd84fd38b0b76f57b31f1eba508
font_01_sfnt_off0000fe2d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE2D 11416 bytes
SHA-256: 1de8bc2f793514f0b53ae584de167592c23dd11dfe643ff10510420f4ac0f6f5