Malicious PDF — malware analysis report

Static analysis result for SHA-256 21b590a7ef18afc9…

MALICIOUS

PDF

98.6 KB Created: 2021-07-14 05:45:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 71017d5751f417948ec2369a42ed8eed SHA-1: c1b99c54e0f0d748a49abf62a91991446796c5af SHA-256: 21b590a7ef18afc961fdd12cc3eca6988b273c084a9ece264d06e9d6ab39ceb4
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics indicate it functions as a link farm, pointing to compromised CMS uploads and disposable hosting, suggesting a phishing or malware distribution scheme. The embedded URLs, such as http://adhdadvisory.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cfe0420bab---13554052514.pdf, are key indicators of this activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9928

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://www.northamericatalk.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c74676d68d0---favunetiragenusuz.pdf In PDF document text
    • https://k-barrierfree.com/FileData/ckfinder/files/20210707_1D6CAE22573D3598.pdfIn PDF document text
    • https://loskutova.site/wp-content/plugins/super-forms/uploads/php/files/62df085cdb8a18df39b245397a7a0da8/xinawofidexajaxumi.pdfIn PDF document text
    • https://osikovo.eu/webroot/img/content/files/demonuvuzojabitipigidar.pdfIn PDF document text
    • https://expungemyrecordnj.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e59780b6351---72012663280.pdfIn PDF document text
    • https://agribusiness.pk/wp-content/plugins/formcraft/file-upload/server/content/files/1607486d6854f6---18009657533.pdfIn PDF document text
    • http://angelcabrera.com/FCKfiles/file/66143819387.pdfIn PDF document text
    • https://amirep.com/wp-content/plugins/super-forms/uploads/php/files/cbb23e21f80f105fb5e5babca71fe68a/sexoxunesidoxoli.pdfIn PDF document text
    • http://lichnyiybrand.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160ac201d80caa---pevisofesuna.pdfIn PDF document text
    • http://imcborivali.org/userfiles/file/pasusixadowarotoxigoza.pdfIn PDF document text
    • http://adhdadvisory.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cfe0420bab---13554052514.pdfIn PDF document text
    • https://conexus-study-abroad-travel.com/ckfinder/userfiles/file/66480615344.pdfIn PDF document text
    • https://www.3dreamchurch.com/wp-content/plugins/super-forms/uploads/php/files/1a4b3e304804b61335bfc81037452471/butir.pdfIn PDF document text
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160850fe64656d---67008051996.pdfIn PDF document text
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/160868df82643d---92136386970.pdfIn PDF document text
    • https://worldkelo.com/wp-content/plugins/super-forms/uploads/php/files/5f62e76aa79a71050aeeba88669b0b8a/825407532.pdfIn PDF document text
    • http://altaprecision.com/userfiles/file/sawefegixuluziganowosugel.pdfIn PDF document text
    • http://imagespa.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1607589c4349f9---4543422918.pdfIn PDF document text
    • http://muacuoi.vn/Pictures/files/9197002430.pdfIn PDF document text
    • http://churchillreunion.com/clients/72216/File/55217818925.pdfIn PDF document text
    • https://smartmedia.ro/app/webroot/files/userfiles/files/tixagupuwirujex.pdfIn PDF document text
    • http://cadeco.com/testingsites/advantage_aviation/assets/media/file/kigukekijezinejik.pdfIn PDF document text
    • http://www.studiolegalefusimorelli.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c1054cf3d85---32817065550.pdfIn PDF document text
    • http://aiskreunion.com/clients/b/b4/b417c2091670ce0b0d78f4b231aea02c/File/38869414910.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=freaky+texts+to+send+himPDF 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_off00011f74.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F74 16872 bytes
SHA-256: a1a07711c4c62aa44f36453a30c1af4357f8706dd7a54840ea7f552f5373f886
font_01_sfnt_off00014b25.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14B25 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001633c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1633C 10752 bytes
SHA-256: 2317ba2d1aa70476f118a9bfd37d280c76eefacef855ab95d2cd458f439369e7

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