Malicious PDF — malware analysis report

Static analysis result for SHA-256 35c7a6e0d83eb8f5…

MALICIOUS

PDF

81.1 KB Created: 2021-08-29 19:27:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: b71a13a6cb0d6493502ac959474b1029 SHA-1: ca61e60f2549abc4945659ba093d5e7bf16d6980 SHA-256: 35c7a6e0d83eb8f5f2ebd7dfe90f3c12fc2da7770092d87cca5f40f2421f6e7b
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many pointing to compromised CMS upload directories and disposable hosting, suggesting a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. No scripts were extracted, and the document body was unreadable, but the heuristic findings are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://tecsal.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160e842dde25db---vatodozudo.pdf In PDF document text
    • https://maxflowfans.com/userfiles/file/16161668945.pdfIn PDF document text
    • http://talleresjpg.es/img/file/8363399130.pdfIn PDF document text
    • http://bhhangkhong.com/upload/images/files/ronafademomogijomo.pdfIn PDF document text
    • http://thepnguyentran.com/media/ftp/file/14850206846.pdfIn PDF document text
    • https://dansobentre.net/uploads/file/7554040159.pdfIn PDF document text
    • https://vietspices.asia/uploads/files/fizulopevupiwopezew.pdfIn PDF document text
    • https://jnfarley.com/wp-content/plugins/super-forms/uploads/php/files/bn24fugovpotecrar20pgvcnh1/ledesimezesilipaviwopof.pdfIn PDF document text
    • https://infravoip.com/wp-content/plugins/super-forms/uploads/php/files/dc5bd742592ab70a522d1952f2f238c7/1385685480.pdfIn PDF document text
    • http://studiolaviano.it/userfiles/files/20691414129.pdfIn PDF document text
    • https://vieclamkinhdoanh247.com/upload/files/dowusopepagunajeka.pdfIn PDF document text
    • http://analogsys.com/uploaded/file/1341600076608fb5bad6daa.pdfIn PDF document text
    • http://training-solutions.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160b96f67b4efe---zesatigujepulev.pdfIn PDF document text
    • https://interativacorretora.com/fotosempresa/files/53789958983.pdfIn PDF document text
    • http://triumphtoday.org/wp-content/plugins/formcraft/file-upload/server/content/files/160c1676c8e4f6---55755468521.pdfIn PDF document text
    • http://www.rec39.ru/wp-content/plugins/super-forms/uploads/php/files/b8273180c0512e36872b23d9007c0284/wiresawu.pdfIn PDF document text
    • http://getawaynewzealand.co.nz/wp-content/plugins/formcraft/file-upload/server/content/files/160a3d35138940---2719099551.pdfIn PDF document text
    • http://etcad.net/np/upfile/file/dazivo.pdfIn PDF document text
    • http://www.patricktennis.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160db3fc25debe---52237885963.pdfIn PDF document text
    • https://habibitours.com/ckfinder/userfiles/files/48218195353.pdfIn PDF document text
    • http://tunglamgarden.com/images/fck/file/gaxulijafumafixame.pdfIn PDF document text
    • http://www.urbanwaterways.info/files/muzalopo.pdfIn PDF document text
    • http://studiopassarotti.it/userfiles/files/51289786860.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=meaning+of+former+in+englishPDF 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_off0000d899.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD899 17848 bytes
SHA-256: c03a399763a51ed31b3ac79962d6775c4762149077002f891d2b3b5d1ec071b3
font_01_sfnt_off0001071d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1071D 10556 bytes
SHA-256: cfcc223fdb331510b7b37b58373750e3b1dd9ac58899abd53e307637f5f6b103
font_02_sfnt_off00011ee8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EE8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1