Malicious PDF — malware analysis report

Static analysis result for SHA-256 a7fcfe524699db7f…

MALICIOUS

PDF

77.8 KB Created: 2021-09-22 18:19:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-20
MD5: 88ee2556f71902baf9e52bd9e2ea6c7a SHA-1: ade7853220f81f726fae56532bb0688da6cb970d SHA-256: a7fcfe524699db7f460cf9054abfee74eb9733d5e0b14ac322c24a19de60f260
126 Risk Score

Malware Insights

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

The PDF was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The presence of numerous unique URLs, many pointing to disposable domains, strongly suggests a link farm designed to redirect users to potentially harmful content. The document body, though heavily obfuscated, contains metadata from wkhtmltopdf, suggesting it was programmatically generated to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9943

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://fanti-fitness.pl/uploads/assets/file/8387132236.pdf In PDF document text
    • https://techlan.pl/files/file/18540115996.pdfIn PDF document text
    • https://299-45.com/CKEdit/upload/files/56305002033.pdfIn PDF document text
    • http://headrepublic.pl/images/files/53171646256.pdfIn PDF document text
    • http://sabaispa.net/userfiles/file/ginufusatufopumuteju.pdfIn PDF document text
    • http://falegnameriacastiglione.it/userfiles/files/99191705851.pdfIn PDF document text
    • https://unicon-msk.ru/data/files/26509694688.pdfIn PDF document text
    • http://kraemer-duennebacke.de/files/file/86673301990.pdfIn PDF document text
    • http://aitrans.org/UploadFile/file/F1202109212200538710.pdfIn PDF document text
    • http://atut-biuro.com/uploaded/file/rexewijakew.pdfIn PDF document text
    • https://fundacjaartfreeart.pl/userfiles/file/korifix.pdfIn PDF document text
    • https://fond.ru/userfiles/file/41917735170.pdfIn PDF document text
    • http://gonzagafood.com/userfiles/files/puvevinusovukij.pdfIn PDF document text
    • http://sarljarry.fr/userfiles/file/45613663910.pdfIn PDF document text
    • http://lixupeng.com/uploads/files/zepepe.pdfIn PDF document text
    • http://3asoft.vn/img/files/42169349386.pdfIn PDF document text
    • http://tetrafluoro.com/upload/files/wokuju.pdfIn PDF document text
    • http://toptoptraining.ru/img/upload/file/xubefakipobasawedeporozag.pdfIn PDF document text
    • http://erh-hu.com/userfiles/file/16684815578.pdfIn PDF document text
    • http://okfilm.kr/userData/board/file/60389947923.pdfIn PDF document text
    • https://maciejabramowicz.pl/upload/files/file/89090641911.pdfIn PDF document text
    • http://yuanjiangchem.com/upload/files/zefegizipal.pdfIn PDF document text
    • http://menifee.hanasushichoice.com/uploads/files/tunid.pdfIn PDF document text
    • http://wowbond.com/upload/Fckeditor/file/27681186475.pdfIn PDF document text
    • http://alpinist.store/sribati/editor/uploadfiles/tujurovazataboditefajel.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=code+anime+dimensionPDF 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_off0000cf64.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF64 16868 bytes
SHA-256: 19fab4030b19410815cdbf06282f6417bbcf1bdd6cb0717a08a0e76de2853b05
font_01_sfnt_off0000fb25.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB25 10196 bytes
SHA-256: c8bb5d186dfe1dcf82d9c06796da68663d94096957a4e3cc741096a0cd4068ab
font_02_sfnt_off000111f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111F3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1