Malicious PDF — malware analysis report

Static analysis result for SHA-256 255b594d23a918ba…

MALICIOUS

PDF

94.2 KB Created: 2021-09-05 18:56:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 9487016c0b965e8055e4c0b4f8a54c31 SHA-1: 0c5ea9b789ec2382acc0bc935cf503f99dbbf8ed SHA-256: 255b594d23a918ba9f24925992166481e8c9dafc01bc72dee268b80b492eb50f
164 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment

The sample is a PDF document containing embedded JavaScript, which is a common technique for executing malicious code. It also features a large number of external URLs, many pointing to compromised CMS upload directories, suggesting a phishing or malware distribution campaign. The ClamAV detection and ML classifier strongly indicate malicious intent, likely related to phishing or delivering a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://archism.ru/uplcv?utm_term=simple+present+interrogative+form+pdf PDF link annotation
    • https://www.financedeclined.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160aa896737b5f---56792270626.pdfIn PDF document text
    • http://lycee-elm.org/userfiles/file/bomugojokel.pdfIn PDF document text
    • https://www.cir.cloud/wp-content/plugins/formcraft/file-upload/server/content/files/160815d7b8a515---vunaxebemadosov.pdfIn PDF document text
    • https://area34.info/wp-content/plugins/super-forms/uploads/php/files/9hkv07el1v79ftreesrbc1em72/sunomepujoxobekureven.pdfIn PDF document text
    • https://assignmentmart.com/ckfinder/userfiles/files/47433433077.pdfIn PDF document text
    • https://peiitw.com/Upload/ckeditor/files/76380443995.pdfIn PDF document text
    • http://lookupagency.es/wp-content/plugins/formcraft/file-upload/server/content/files/16078143d8f98f---kagol.pdfIn PDF document text
    • http://zhongguohuachun.com/d/files/badogenowefuzawugexarev.pdfIn PDF document text
    • https://www.bouldersudbury.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607d0c5b47152---98185757282.pdfIn PDF document text
    • https://iamluno.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f104141825---3214965945.pdfIn PDF document text
    • https://feriaesotericadeatocha.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aebb5b0afd9---riponepixiz.pdfIn PDF document text
    • http://www.tobywells.org/media/fckdir/file/doxizivazub.pdfIn PDF document text
    • http://drinkandshrink.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160b4cc6bd805b---pafafi.pdfIn PDF document text
    • http://intechsol.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1606d8a7276c84---57237644853.pdfIn PDF document text
    • https://stewsites.com/wp-content/plugins/super-forms/uploads/php/files/6eb6c8c87fec9146accc7d55f3d6f387/zaramiwem.pdfIn PDF document text
    • https://alternatifhirdavat.com/upload/ckfinder/files/towekebozaginix.pdfIn PDF document text
    • http://jyjwqj.com/uploadfile/file///2021072922075958.pdfIn PDF document text
    • https://www.ogblfrontaliers.fr/wp-content/plugins/super-forms/uploads/php/files/sfe18tshbpte07hu3jv1j0rcfk/vurenogejebevusus.pdfIn PDF document text
    • http://rund.cz/UserFiles/File/witifisulogujipopepiroma.pdfIn PDF document text
    • http://www.stratcareerservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/161004cd63bd6f---zufabezopuvovapa.pdfIn PDF document text
    • http://aeskulap24h.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c8885531ba7---dadagu.pdfIn PDF document text
    • https://smlstripedbass.com/home/rock/public_html/ckfinder/userfiles/files/temib.pdfIn PDF document text
    • http://homenet-spb.ru/userfiles/file/melepomoxufewelaw.pdfIn PDF document text
    • https://sfasg.jp/js/ckfinder/userfiles/files/nagexodavituxumab.pdfIn PDF document text
    • 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_off0001059f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1059F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011db6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DB6 10984 bytes
SHA-256: 102432a6fa178aa34ccfffaebfd0eff1fc0c402481610f6b2d5a66fe3cd31516
font_02_sfnt_off000136f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x136F5 19928 bytes
SHA-256: 0bdeef011c6b1cd2d9b11ade2bff77f5df88a1820d6908674a54e415e94c96d3

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