Malicious PDF — malware analysis report

Static analysis result for SHA-256 aa84384b77f4e7a3…

MALICIOUS

PDF

86.6 KB Created: 2021-08-16 04:47:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-17
MD5: 2fa2125c6101bcdd4d871eefa8f4f8dc SHA-1: 870ee0a2ae9889e40cebc83e4d13c0ff8c111f84 SHA-256: aa84384b77f4e7a31f662ab2b20edaafa21da309e712fce5efc97d8db2bc670d
156 Risk Score

Malware Insights

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

The PDF was identified as malicious by ML classifiers and ClamAV, with high-confidence heuristics indicating it functions as a link farm. Multiple URLs point to compromised CMS upload storage, suggesting an attempt to lure users to malicious sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content but containing numerous embedded URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9979

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://noks.cz/wp-content/plugins/formcraft/file-upload/server/content/files/160a2ac1d66f5b---11945985968.pdf In PDF document text
    • http://adamlegal.com/userfiles/file/gikamunesewesi.pdfIn PDF document text
    • http://lookupagency.es/wp-content/plugins/formcraft/file-upload/server/content/files/1609a7314a4710---wazivovujapuxobaruk.pdfIn PDF document text
    • https://gresathouse.com/wp-content/plugins/super-forms/uploads/php/files/72632224f3916a7dd0724fc885b8fcfe/wifolimubeso.pdfIn PDF document text
    • http://ergo-logo-bamberg.de/userfiles/file/dumugokevuzov.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1608c3738646fd---vozatarelasebidumovumeka.pdfIn PDF document text
    • https://belgradenightlife.info/wp-content/plugins/super-forms/uploads/php/files/k7h6c9p9lssra9e55rb32531mr/lunoziripirenawubi.pdfIn PDF document text
    • http://madonnina.info/userfiles/files/femaluzedelolemowagobenef.pdfIn PDF document text
    • http://careerdynamic.com/clients/3/3d/3d9dba0a3645e5854abf1db7654b9c86/File/87626808697.pdfIn PDF document text
    • http://asijskepotraviny.cz/files/file/72414651510.pdfIn PDF document text
    • http://www.fashiongale.ro/userfiles/files/bejitotolesolak.pdfIn PDF document text
    • https://flardochform.se/userfiles/file/15840987418.pdfIn PDF document text
    • http://thevenetianmask.com/clients/71561/File/49845330211.pdfIn PDF document text
    • http://gshosnab.ru/userfiles/file/65929725267.pdfIn PDF document text
    • http://cupta.org/userfiles/files/20210613092719.pdfIn PDF document text
    • https://www.karenlovelee.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0f8665a65c---184962264.pdfIn PDF document text
    • https://hpx.com.ua/wp-content/plugins/super-forms/uploads/php/files/7066828c0b93378c510fb18c444e966c/43050124696.pdfIn PDF document text
    • http://www.christinemartin.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160921a8461501---somut.pdfIn PDF document text
    • https://sipsib.ru/wp-content/plugins/super-forms/uploads/php/files/509ad42b6aca6dfce6b4d860d2de2516/37001540922.pdfIn PDF document text
    • https://stillwaiting.org/userfiles/file/69800704097.pdfIn PDF document text
    • https://www.alertgy.com/wp-content/plugins/super-forms/uploads/php/files/6d307771c2c7aa0c43b55c6ee014c1cc/vopisebezofefinifew.pdfIn PDF document text
    • https://athensviptour.com/wp-content/plugins/super-forms/uploads/php/files/2f6f573eac14f51b8da6dab76a485e48/20958345191.pdfIn PDF document text
    • http://rainbowcaterers.in/userfiles/file/39973216172.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=ejercicios+de+grafomotricidad+6+a%C3%B1os+para+imprimir+pdfPDF 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_off0000e54d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE54D 19212 bytes
SHA-256: de0c843c08f94d61279a0e87e21b2c0f2de030638f81338b534108f4f87877ab
font_01_sfnt_off00011632.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11632 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012e49.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E49 11300 bytes
SHA-256: 865ec06076290c0f760cf80b1374d2d43e1c275cad1df50c8a4b77b279fcef86

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