Malicious PDF — malware analysis report

Static analysis result for SHA-256 855c08a874309f8d…

MALICIOUS

PDF

87.7 KB Created: 2021-07-03 13:12:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: b304fcc447e5f4480b3aee47636744d1 SHA-1: a8497ff9e29c3deb59b7a6d4d1f53cb68d64fece SHA-256: 855c08a874309f8d1301488f3d4e4c12feec2b255133399fb92c19dcd9a9ee2f
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to compromised WordPress sites. These links likely serve as lures for phishing attacks or to distribute further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

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://puertoestereo.com/wp-content/plugins/super-forms/uploads/php/files/q3u3mcv1rbaosvb4gv9er7n7e4/84294629917.pdf In PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/160a2bd49da3b6---vevom.pdfIn PDF document text
    • https://popcouncilinstitute.org/wp-content/plugins/super-forms/uploads/php/files/fe72f22a88faabc10e97bdcef2c67af3/vipowabosaxe.pdfIn PDF document text
    • http://amon-syotengai.com/userfiles/file/20537086920.pdfIn PDF document text
    • https://micro-churches.net/uploads/file/kunufoxodebivaterax.pdfIn PDF document text
    • https://www.napariverinn.com/wp-content/plugins/super-forms/uploads/php/files/b1ad66c6f2d31844be52c7ef6769c01c/71189246606.pdfIn PDF document text
    • http://fantasypartyentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081791612248---50769129188.pdfIn PDF document text
    • http://www.rannatennis.ee/data/upfiles/files/filurizo.pdfIn PDF document text
    • https://www.revistadefiesta.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a780fcef8ca---jazujekelarexefudojagir.pdfIn PDF document text
    • https://lightsourceindiana.com/wp-content/plugins/super-forms/uploads/php/files/5a8ab973471898bcf5c03a474c46255b/67183465141.pdfIn PDF document text
    • https://broadstripe.com/wp-content/plugins/super-forms/uploads/php/files/f4877c67c5245dc6da6e2de7d781c7ef/70664393298.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/160894fc4435ee---jigopedonevudototepateka.pdfIn PDF document text
    • https://svetpoznaniyaonline.ru/wp-content/plugins/super-forms/uploads/php/files/f65b370050f66de8286139b117dae545/40454697524.pdfIn PDF document text
    • http://yatros.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1608675d87d568---wesuminisugazijal.pdfIn PDF document text
    • https://ahha.az/userfiles/file/46204952486.pdfIn PDF document text
    • http://mirrorgallery.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079c3d14e60d---wiwisu.pdfIn PDF document text
    • http://www.ashtralmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/160db9bdcb9db6---gararoxetu.pdfIn PDF document text
    • https://extremetour74.ru/wp-content/plugins/super-forms/uploads/php/files/95442e8a1c155366a39c63b889bc0b98/wugeg.pdfIn PDF document text
    • http://cedule-plachty.cz/files/file/witusalavixovonakaduvev.pdfIn PDF document text
    • https://aljazeerahdrilling.com/userfiles/files/71251008633.pdfIn PDF document text
    • https://fermuar.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a0ebab679e5---loxunugojimaw.pdfIn PDF document text
    • http://mg001.cn/upload_fck/file/2021-5-25/20210525145240389620.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=best+remote+companies+to+work+for+2020PDF 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_off0000f36b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF36B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010b82.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B82 11068 bytes
SHA-256: e9302751f7ecc480293204a845171912acec329a3e1efc8c4906bc42e71128bd
font_02_sfnt_off00012578.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12578 16828 bytes
SHA-256: 8544a7f604bd1003a3337af2091f223fc109cdc3333ef4045a8e033833ded0d2

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