Malicious PDF — malware analysis report

Static analysis result for SHA-256 23a5a4a3d84fe4cc…

MALICIOUS

PDF

92.5 KB Created: 2021-09-20 07:11:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 78858a003f650947eeb051c14f0e18ed SHA-1: e54c03a09845ad771cd0f208f7ea78d895de1691 SHA-256: 23a5a4a3d84fe4ccd02599e2c177659048a7caa9faf621dc367bb6751acf44f8
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document was flagged by multiple heuristics as malicious, including a ClamAV detection for Pdf.Phishing.Trojan. The presence of numerous external URIs, many pointing to compromised CMS upload storage or disposable hosting, indicates a link farm designed to redirect users to potentially malicious content. The ML classifier also strongly indicated maliciousness. No scripts were extracted, but the PDF structure itself facilitates the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9959

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://smidgel.ru/uplcv?utm_term=%E1%BB%A9ng+d%E1%BB%A5ng+ch%C6%B0a+%C4%91%C6%B0%E1%BB%A3c+c%C3%A0i+%C4%91%E1%BA%B7t+android PDF link annotation
    • http://www.como-grup.ro/fisiere/file/busarotodup.pdfIn PDF document text
    • http://gamax-motor.cz/data/dokumenty/20944488823.pdfIn PDF document text
    • https://infosantiere.ro/userfiles/file/25477178126.pdfIn PDF document text
    • https://dorfadvertising.com/ckfinder/userfiles/files/31245528827.pdfIn PDF document text
    • https://rpaxis.net/userfiles/file/48910157043.pdfIn PDF document text
    • https://sierrainstruments.cn/fckeditor/editor/filemanager/connectors/php/fckeditor/upload/202109/file/15520730288.pdfIn PDF document text
    • http://obraz-tlt.ru/userfiles/file/tezumujisufadorutizakegum.pdfIn PDF document text
    • http://tndgdemo2.com/ckfinder/userfiles/files/dubakukepaguvo.pdfIn PDF document text
    • http://kosmonautika.ee/ckfinder/userfiles/files/18983411915.pdfIn PDF document text
    • http://mrtowing.ca/Lawyers/userfiles/file/1405353108.pdfIn PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/dqg0rk7r81usm8b9u3780s21l3/fajakevisopukumel.pdfIn PDF document text
    • https://www.assofmt.org/ckfinder/userfiles/files/69095540431.pdfIn PDF document text
    • http://186086.com/upload/files/4959653448.pdfIn PDF document text
    • http://candientu24h.vn/webroot/img/files/86049605654.pdfIn PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138b0a8126e1---88227887027.pdfIn PDF document text
    • http://www.nuricomuvakfi.org/wp-content/plugins/super-forms/uploads/php/files/o1egnh3re6o4ik7i8o0cc69fi3/24375352781.pdfIn PDF document text
    • http://devitohomesorlando.com/userfiles/files/temutawebugezozez.pdfIn PDF document text
    • https://cooperspick.com/files/nipotanukaxorotu.pdfIn PDF document text
    • http://refinerlink.com/userfiles/file/21682345517.pdfIn PDF document text
    • http://artgrafika.cz/userfiles/file/jorimiva.pdfIn PDF document text
    • https://adetexfoamgroup.centralcms.cloud/galeria/files/kokusosonezo.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dd7e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD7E 16564 bytes
SHA-256: 4cae5e31a18c985d738e41dd9f9bd03c8c5df24a958b83e3f1a199490e78700d
font_01_sfnt_off0000f4de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF4DE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010cf0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CF0 29940 bytes
SHA-256: 8286ab2d6d21f889a6d51e6997d3a6a7913d9ca9ac762bfbe9ebda97227edc7b
font_03_sfnt_off000148a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x148A1 11576 bytes
SHA-256: f1e87d6f8a80218032fc3319be7e048b3ee2ee55ad92550564b50cb9220f1783

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