Malicious PDF — malware analysis report

Static analysis result for SHA-256 fbcda9176694b16a…

MALICIOUS

PDF

81.3 KB Created: 2021-08-26 04:33:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 23c578c2891d75978071d533230db239 SHA-1: ec7446732107f92f68646ed32349844611cb1964 SHA-256: fbcda9176694b16a5fa6ee5a17e86dbc2eb8cb8e78b53ec8a13fa3bfdb72d6b5
156 Risk Score

Malware Insights

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

This PDF file was flagged as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with many URLs pointing to compromised CMS upload storage and disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links. The primary attack pattern involves directing users to potentially malicious external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608a73d6a9eba---59418559583.pdf
    • http://barrarioservicos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a64685a0e4c---lovosadugesisedupukamusam.pdf
    • http://rambud.pl/uploaded/file/simozimufudazovivuxegofus.pdf
    • http://kondicionery-shodnya.ru/upload_picture/file/fevemexibexubog.pdf
    • http://satakantaresort.com/user_img/files/25876565004.pdf
    • https://pratham.one/file/faxegajaruwuwi.pdf
    • http://xn--b1ahhafccpgkb2bxo.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/c9873b6cbdde1ac735f7015f8962e3d4/kukov.pdf
    • https://hssanesteban.cl/files/lugulideno.pdf
    • http://pkpneu.cz/userfiles/file/63147568310.pdf
    • http://auburn-companies.com/userfiles/files/61641823958.pdf
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/1jp60udmu8oi60d5t61p3r0bm0/kazutipe.pdf
    • https://aduanaldelvalle.com/userfiles/file/femelewukudedupikob.pdf
    • https://charteriraq.ir/basefile/charteriraqir/files/guralagaradamidukevoro.pdf
    • https://icbacademy.com/upload/files/kizakixirelavefavuxeko.pdf
    • https://feltshoe.com/userfiles/file/nokojajuzad.pdf
    • http://cnpair.com/userfiles/file/61844751985.pdf
    • http://ahchala.com/img/file/25567557619.pdf
    • https://dentinale.eu/wp-content/plugins/super-forms/uploads/php/files/541da9def810c0fb6172649659c05cbe/ranurexuxaxuz.pdf
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/1608605e1c5dcd---zilutedaj.pdf
    • https://hoovermaids.com/wp-content/plugins/super-forms/uploads/php/files/694724502ec6bdc54c6a15693777f5d6/22774498276.pdf
    • http://haiphongcontest.com/images/files/31061707826.pdf
    • http://denledmpe.com/upload/files/78976747944.pdf
    • https://linhngapt.vn/upload/files/18197572620.pdf
    • http://score1forspencer.com/clients/4/45/4587145e2679cb7673d0e21b436e5c25/File/39663074452.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=activity+understanding+dna+structure+answer+key
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ddfd.bin
b0b38fc1ca2ad2a1eb3f28dd23804cb17cb5f90d1366fb5605bad308ff113933
pdf-font-stream PDF embedded font (sfnt) at offset 0xDDFD 10820 bytes
font_01_sfnt_off0000f701.bin
5d26ebc2e217c56b00a8eb6594f01502bf0327ad729bc364d8db527423e46129
pdf-font-stream PDF embedded font (sfnt) at offset 0xF701 15676 bytes
font_02_sfnt_off00011f5f.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11F5F 16792 bytes