Malicious PDF — malware analysis report

Static analysis result for SHA-256 55a805935d8ac55c…

MALICIOUS

PDF

69.6 KB Created: 2021-09-21 23:03:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: d50e5bd19760fbbaa20e8e62ead77a86 SHA-1: f397e8adb15b797caa853b5f0c3120b891386adc SHA-256: 55a805935d8ac55cafaed8ba3c87322b099adccc75406ed26a55de4990428f73
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 or disposable hosting, indicative of a link farm designed to host malicious content. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution through these links. No scripts were extracted, and the document body was unreadable, but the heuristic firings clearly point to a link-farming attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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 http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613d1cb8e5891---bamoxidusodebejatabekubab.pdf In PDF document text
    • http://benrassam.com/uploads/files/koxasamakav.pdfIn PDF document text
    • http://www.adarshvidhyasankul.org/userfilesfile/tesinoweditatawobize.pdfIn PDF document text
    • http://daglichtfilters.nl/ckfinder/userfiles/files/lekiliruvakixitorek.pdfIn PDF document text
    • http://kastely-vacduka.hu/fileok/file/59482443437.pdfIn PDF document text
    • http://panel2conso.com/userfiles/file/15134185997.pdfIn PDF document text
    • https://velvetskin.pl/wp-content/plugins/super-forms/uploads/php/files/dd45d56866d8f528810bfa25c5e31ec2/83251070935.pdfIn PDF document text
    • http://gzmingjun.com/uploadfile/files/20210907_090931.pdfIn PDF document text
    • http://xn--djr00fsyfv0o5qgy9u.net/filespath/files/20210913225008.pdfIn PDF document text
    • https://7foro.exceltur.org/exceltur_nuevo/ckfinder/userfiles/files/toganisum.pdfIn PDF document text
    • http://trackeg.com/en/wp-content/plugins/formcraft/file-upload/server/content/files/161413f86ab0e4---rogegiximu.pdfIn PDF document text
    • http://gorillatheory.com/admin/upload/file/bixipiwejidozusi.pdfIn PDF document text
    • http://www.guaitoli.eng.br/wp-content/plugins/formcraft/file-upload/server/content/files/16137ddfdd07b9---ripuf.pdfIn PDF document text
    • http://normel.org/files/upload/file/75313759752.pdfIn PDF document text
    • http://mobilahomedesign.com/userfiles/files/vupemozanetudoleseva.pdfIn PDF document text
    • https://mandarinusa.com/userfiles/file/1630885791.pdfIn PDF document text
    • https://pediatricpotentialsnj.com/PP/PPpng/files/38065984483.pdfIn PDF document text
    • http://www.bsa.by/ckfinder/userfiles/files/relugevorit.pdfIn PDF document text
    • https://amityhr.com/userfiles/file/41210946924.pdfIn PDF document text
    • http://www.southforconstruction.com/frontend/web/ckfinder/userfiles/files/40650546015.pdfIn PDF document text
    • http://parilka.by/var/upload/file/mabifukup.pdfIn PDF document text
    • https://pasarantogel2.com/contents/files/58880016213.pdfIn PDF document text
    • http://silverspringabw.com/uploads/files/13183141968.pdfIn PDF document text
    • https://berbagiangka.com/contents/files/81124927877.pdfIn PDF document text
    • https://photographerin.agency/wp-content/plugins/super-forms/uploads/php/files/9a8ja74cdi9mibpt2rs19pkei7/xalevixafuzaxuse.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=play+install+referrer+library+examplePDF 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_off0000b193.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB193 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c9a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9A5 15324 bytes
SHA-256: ccdac1caa0c98f1dc98c3959e2f21313f75742e7c76d7142352c9cc3ffaeb345
font_02_sfnt_off0000f03e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF03E 10756 bytes
SHA-256: 33914e8aa4c1e34e900b0c7bb8a32362bc06fb90b40099b4fda25f96c034bf5d