Malicious PDF — malware analysis report

Static analysis result for SHA-256 6a3237fe1bfbbd5b…

MALICIOUS

PDF

91.3 KB Created: 2021-06-30 16:17:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: be748aff5d6a9ea85cde216fbb0d7efb SHA-1: f4a46216d723acc58a6083ba719270ddfced8bdc SHA-256: 6a3237fe1bfbbd5b74b50a023a54b47a2f5b81b0b73d54e920c8e612d9c7777c
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 as malicious. Heuristics indicate it functions as a link farm, with many URLs pointing to compromised WordPress upload directories. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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 http://kystop.com/wp-content/plugins/super-forms/uploads/php/files/b01f44tda2qacmacb7kv6183d4/lovopawa.pdf
    • http://artpolinakuzina.ru/pict/file/detujezila.pdf
    • https://ecobox.eng.br/wp-content/plugins/super-forms/uploads/php/files/m615q0o8gvfa4c14dlqlhku5ir/61989797107.pdf
    • https://www.expoagrogto.com/wp-content/plugins/super-forms/uploads/php/files/i1l6pigsv0upatldpt68tjncj6/92761218268.pdf
    • http://mirandatutoringcentre.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16089dbd920820---50470189796.pdf
    • http://kolkandkolkdesign.com/site/data/ws/files/vonesefagupe.pdf
    • http://lookkorea.net/userfiles/file/zudofi.pdf
    • http://www.idenet.net/wp-content/plugins/formcraft/file-upload/server/content/files/160b6100be4e6a---mevepubuvarogutaxipem.pdf
    • https://www.chauffeur-prive-nice.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160a596a021839---97317778902.pdf
    • https://www.toptalentusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e01ee527f0---xotemos.pdf
    • https://flvirginia.com/wp-content/plugins/super-forms/uploads/php/files/ed60084ad5bfdcefcc2d9fa7001529d0/mivuzegu.pdf
    • https://pankalconstructora.com/wp-content/plugins/formcraft/file-upload/server/content/files/16093c56d35693---66220459883.pdf
    • https://vidolamerica.org/wp-content/plugins/super-forms/uploads/php/files/b2a2833a18b8dc42bbbbc1dbcc28f20d/dominasajukebiforubivid.pdf
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cd6e7b3a17f---3828045248.pdf
    • http://anvlaw.com/userfiles/file/lunobuzajebamowadida.pdf
    • http://j-line.ca/fck_upload/file/18883500487.pdf
    • https://www.alpha-dynamics.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1608bc999af0a7---68604839361.pdf
    • https://pavaniautismschools.com/wp-content/plugins/super-forms/uploads/php/files/al9hf441nvr850jhce79ih0dct/28981208757.pdf
    • http://innotack.com/userfiles/files/19201921039.pdf
    • http://iccj.jp/images/uploads/fckeditor/file/talopobepejofe.pdf
    • http://peaceinsrilanka.lk/userfiles/file/29550713683.pdf
    • https://mygamedaysports.com/wp-content/plugins/super-forms/uploads/php/files/6e5e95f6699efbb000748715ced51c8e/jonomefexuxotetoxuziw.pdf
    • http://caratow.eu/userfiles/file/risugomidelepijude.pdf
    • http://wasserburg.pl/userfiles/file/xulatekatosaviwevupoze.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=puppy+color+by+number
    • 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_off0001021c.bin
427e9accf70d99c5ed85eec806fdd8b8b518cae51c532e2d51a7b588373779f0
pdf-font-stream PDF embedded font (sfnt) at offset 0x1021C 10372 bytes
font_01_sfnt_off00011953.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11953 16792 bytes
font_02_sfnt_off00013165.bin
de2ed0182c596d4e9e74f8363e2528222136795c2d24dd7e3099125a5cd9568d
pdf-font-stream PDF embedded font (sfnt) at offset 0x13165 17720 bytes