Malicious PDF — malware analysis report

Static analysis result for SHA-256 81350b23fcd40f55…

MALICIOUS

PDF

82.7 KB Created: 2021-09-04 08:02:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 2be3493535a0e5cbce9f521e6f835d65 SHA-1: 5beba32e8c02d96523c02915beb0190832501027 SHA-256: 81350b23fcd40f55a4ea2e1237fa6e652cf0497508ebb727a40252730da32dba
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier, indicating malicious intent. It contains a link farm with numerous external URLs, many hosted on compromised CMS platforms, suggesting a tactic to distribute malicious content or manipulate search engine results. The presence of multiple distinct hosts and the use of UTM parameters in one URL further support a link farm or SEO poisoning attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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://wxdyzs.com/userfiles/files/18105521540.pdf In PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/160e482634c56d---jivevotoroladiru.pdfIn PDF document text
    • https://elearning-chemistry.ro/userfiles/file/rokimusaruwosisibukeve.pdfIn PDF document text
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/16cqc2bosrvt4n0rd5p1av64r2/3800550355.pdfIn PDF document text
    • http://www.de.ruben.pl/ckfinder/userfiles/files/mojenaf.pdfIn PDF document text
    • https://aguiapromocional.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16083eb3765984---dekurawesuk.pdfIn PDF document text
    • http://sukhonthip.com/file_media/file_image/file/56665711162.pdfIn PDF document text
    • http://tercovci.cz/files/file/rusalusukexol.pdfIn PDF document text
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1608c0bc097e85---85365034206.pdfIn PDF document text
    • http://fonnepal.org/userfiles/file/91898329982.pdfIn PDF document text
    • http://2ds-creations.fr/userfiles/file/36431334576.pdfIn PDF document text
    • http://www.hkqi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b54164a52ff---14504192596.pdfIn PDF document text
    • https://www.hed-endo.hr/wp-content/plugins/formcraft/file-upload/server/content/files/1611ef53d70445---nadazizirewulumoruf.pdfIn PDF document text
    • http://areaengineeringsrl.eu/userfiles/files/24685708707.pdfIn PDF document text
    • https://www.spreefahrten-berlin.de/wp-content/plugins/super-forms/uploads/php/files/hk592g09brfdbpd29baml500jn/kutumusofapate.pdfIn PDF document text
    • http://halmar.info/userfiles/file/bapolotutubemudisuzale.pdfIn PDF document text
    • https://villatoscana-pi.it/userfiles/file/konodakolaguwigiwoz.pdfIn PDF document text
    • http://neuragen.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160fb497d29020---63013501830.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608bcfa198046---wubonigivuxipogob.pdfIn PDF document text
    • http://mvsexpo.ru/admin/ckfinder/userfiles/files/lewozeme.pdfIn PDF document text
    • https://www.jemelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609876f682a27---wuvopoxamufoloxowed.pdfIn PDF document text
    • http://www.boldino-hotel.com/ckfinder/userfiles/files/88376898333.pdfIn PDF document text
    • https://thepetrichortouch.com/wp-content/plugins/super-forms/uploads/php/files/hoqev9602ba2ed3ifrksh5ea2r/29534312751.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=find+the+hazards+in+the+kitchen+worksheetPDF 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_off0000dfe2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFE2 10636 bytes
SHA-256: e2e0591ce3cd34f6c0d1f6232a1fb91c7129b183723d6d718b02340e03607e82
font_01_sfnt_off0000f848.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF848 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001105a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1105A 17324 bytes
SHA-256: ca9d2e15a54ceddc721bc4dc5bbd734f30b3cb90fb7f5bca032cb757f9e9b3a8

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