Malicious PDF — malware analysis report

Static analysis result for SHA-256 71ca999f1a5dc583…

MALICIOUS

PDF

82.3 KB Created: 2021-07-22 15:44:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 7c62f7af58e6c1d76ab8b3e523846ba5 SHA-1: 86e6197fc554c08d09f3a98b5c306531dc5d31b1 SHA-256: 71ca999f1a5dc583ce1a6cbef71e37ad5e62322df5e1edfeef24c0beb973bb2d
156 Risk Score

Malware Insights

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

This PDF sample was flagged by multiple heuristics as a link farm, with many URLs pointing to potentially compromised WordPress sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to lure users to external sites for further compromise. No scripts were extracted, and the document body was unreadable binary data, suggesting the primary malicious function is achieved through the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1609f47936dc3c---vodelomirinonorate.pdf
    • http://sanfrancescovet.com/userfiles/files/minowilulasawi.pdf
    • https://rybczewice.pl/userfiles/file/fatepiguzonenutoriso.pdf
    • https://musikkursus.dk/userfiles/file/73106936958.pdf
    • http://trlgpc.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/1830086959.pdf
    • https://akamercedes.com/images/uploads/files/siwag.pdf
    • http://istrouma1971.com/clients/9/9b/9b88b062b8d6af44b28e209fcb06d7d5/File/345113685.pdf
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ac171cc3bd5---94073358379.pdf
    • https://duext.com/wp-content/plugins/super-forms/uploads/php/files/95e933d38641889b3f20d6b326f61358/wunuwipobanilason.pdf
    • http://asirius.su/wp-content/plugins/super-forms/uploads/php/files/a1868732ce58347503a7b8de3c1b3d4a/33605085966.pdf
    • https://mygamedaysports.com/wp-content/plugins/super-forms/uploads/php/files/772b7d48196a4671dd27a3402efa44a0/redidujazekapuvuvaxokutuf.pdf
    • https://chpcentre.com/files/file/44551752604.pdf
    • https://themodernla.com/wp-content/plugins/super-forms/uploads/php/files/a21672caae2592ccb0aa07966fcaca37/lewawabunorumakemoge.pdf
    • http://www.molinoag.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e0bff0d11a2---27090643752.pdf
    • https://bbensonmft.com/wp-content/plugins/super-forms/uploads/php/files/6df38cc619b727e2bb6add665efbaaa6/55490773091.pdf
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c0acff9ac15---1937402591.pdf
    • https://www.reliancecareuk.com/wp-content/plugins/super-forms/uploads/php/files/ebac3c4100fbb3641de03affdf1c5101/67750723114.pdf
    • http://www.fattyweng.com.sg/wp-content/plugins/formcraft/file-upload/server/content/files/1609cf184432a8---8687382807.pdf
    • https://www.wikiwebagency.it/wp-content/plugins/super-forms/uploads/php/files/c423fb4cc3169154d9ff6ba6e7f31b33/95775530971.pdf
    • https://pensionatiitalianiinportogallo.it/wp-content/plugins/super-forms/uploads/php/files/1fa533f761cb9e438eabded3698468a4/witevovoxizixuwabizer.pdf
    • https://farmaciasacoor.com/site/upload/file/jugav.pdf
    • https://g-ortho.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608581325ee73---nuwobibamobupofokedov.pdf
    • https://www.apartamentselsllacs.com/wp-content/plugins/super-forms/uploads/php/files/v3hs84socuq2i570svi073vdgg/36951709351.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=kermit+in+the+swamp
    • 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_off0000df3f.bin
7e1772422d7ddaf382e8e028ec4ac91cad783903b6b557dab9f1d31a15c6623c
pdf-font-stream PDF embedded font (sfnt) at offset 0xDF3F 10428 bytes
font_01_sfnt_off0000f6ba.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF6BA 16792 bytes
font_02_sfnt_off00010ecc.bin
13eb2be2ae581fd5adf20ece3c7d28e67a1083a83675b9806bbdc68aba49fbc7
pdf-font-stream PDF embedded font (sfnt) at offset 0x10ECC 17076 bytes