Malicious PDF — malware analysis report

Static analysis result for SHA-256 a657b3c6de869a09…

MALICIOUS

PDF

74.3 KB Created: 2021-05-07 04:37:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: 16fd0d3e653e255a71380ff64ed719ee SHA-1: 37b6df04d7c6e33565ac3572156d2d6f046272f4 SHA-256: a657b3c6de869a095b371f3b16cf1da94e52adce8f5030d68ec530ada9bcfe0e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious Link

The PDF contains numerous links pointing to compromised WordPress sites, indicating a link farm designed to redirect users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely for phishing or distributing further malware. The embedded URLs are the primary indicators of compromise, facilitating the attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

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://krisoc.ru/uplcv?utm_term=rainmeter+24+hour+clock+format PDF link annotation
    • https://livingcircles.ch/wp-content/plugins/formcraft/file-upload/server/content/files/1608db3fac4ab4---13605631401.pdfIn PDF document text
    • https://izharfoster.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a8f7d8c291---mipabipitasepibabilipu.pdfIn PDF document text
    • http://saamfactory.com/wp-content/plugins/super-forms/uploads/php/files/27e15607c9c4bbcaf369441d175f56cb/kusenuzakepivamedamabal.pdfIn PDF document text
    • https://www.napariverinn.com/wp-content/plugins/super-forms/uploads/php/files/108c11bbfa9a07d176a42c8b0e924545/53185708583.pdfIn PDF document text
    • https://marksiegeldds.com/wp-content/plugins/super-forms/uploads/php/files/e2e8f86390a691ca22116866676d4e20/1599650918.pdfIn PDF document text
    • https://www.kngroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c716d5f6fd---17441977202.pdfIn PDF document text
    • https://kicksomeglass.com/wp-content/plugins/super-forms/uploads/php/files/386a9d3a1743a4e71937bc9d35cd6117/nomorodap.pdfIn PDF document text
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/794eb85b19ef31fd6bf44c1d1d2e2019/gofeperapukalufojumufeduw.pdfIn PDF document text
    • https://personalloan2u.com/wp-content/plugins/super-forms/uploads/php/files/46a6c9d10a484905d838751e472471a6/rutimobo.pdfIn PDF document text
    • https://takeorders.online/wp-content/plugins/super-forms/uploads/php/files/lee76an0edjfr3ijkruhggfe7p/46356668210.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/1608e4f8909ae8---58792485202.pdfIn PDF document text
    • https://amesmedicalservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607071613fca2---36600034137.pdfIn PDF document text
    • https://www.mybizwebsites.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608579d91c8ea---finuxuvek.pdfIn PDF document text
    • https://ddriu.hu/wp-content/plugins/super-forms/uploads/php/files/dc3d32b635e7cd55a1a629dfc7a99efd/8629093502.pdfIn PDF document text
    • https://abofahed.com/userfiles/file/zizufanovexujenarulapa.pdfIn PDF document text
    • https://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/dkluhclecnj1kk8fd7t3l172mt/luzupome.pdfIn PDF document text
    • https://aartipalette.com/userfiles/file/libev.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_off0000e65a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE65A 5236 bytes
SHA-256: 85c61f80b949fd2da13279a483a259e890b98f9db76b9e1d63aed359e65b0456
font_01_sfnt_off0000f80a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF80A 10772 bytes
SHA-256: 4ebeedb4c33ee25a7af14d8cf0b7c6f8889827e3603c37c72f7f92b14400fcaa