Malicious PDF — malware analysis report

Static analysis result for SHA-256 255d3ae0d5b9e1c8…

MALICIOUS

PDF

84.8 KB Created: 2021-09-16 03:25:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: bd33b127404bb6ee55030c28d693fd35 SHA-1: dad711cd5fc5eb93dee8dba5a556fed5647b2ad7 SHA-256: 255d3ae0d5b9e1c82aa46ef8c3f01ae95faf63dee9e43943a7fc5d8fca78097f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which are hosted on compromised WordPress sites, indicating a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with malicious document lures.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://chcial.ru/uplcv?utm_term=svr+camera+apk PDF link annotation
    • http://sarahscupcakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613947ea68f11---55536727108.pdfIn PDF document text
    • http://caribsplash.org/wp-content/plugins/formcraft/file-upload/server/content/files/161417d462dd34---lejigaxamisupexabokatesej.pdfIn PDF document text
    • https://nhahangphongcanh.com/uploads/files/65714770575.pdfIn PDF document text
    • http://deforma.it/userfiles/files/jakukufexagogeza.pdfIn PDF document text
    • https://sadhankendra.org/erc/media/nodovilelapumozomelebo.pdfIn PDF document text
    • http://intertexmedical.com/userfiles/files/fotal.pdfIn PDF document text
    • http://school15-tyumen.ru/f/mukodesamirugew.pdfIn PDF document text
    • http://ydtmuhendislik.com/ckfinder/userfiles/files/17520634216.pdfIn PDF document text
    • https://1sis.com/wp-content/plugins/formcraft/file-upload/server/content/files/161428883c40ee---56753167288.pdfIn PDF document text
    • http://zakuskymoser.cz/www/ckfinder/userfiles/files/30828248834.pdfIn PDF document text
    • http://www.hzkontejnery.cz/ckfinder/userfiles/files/80663947565.pdfIn PDF document text
    • http://phoiinnhiet.com/images/uploads/files/vibebifuruvaguwadawa.pdfIn PDF document text
    • http://german-ex.com/images/blog/file/dokavivesosebibalovi.pdfIn PDF document text
    • https://dpengineerindia.com/admin/userfiles/file/61300216072.pdfIn PDF document text
    • https://artistaone.co/userfiles/files/nofesomerilujo.pdfIn PDF document text
    • https://dcimx.com/files/91516091605.pdfIn PDF document text
    • http://unipell.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613e52160580a---54350860803.pdfIn PDF document text
    • https://billard-hauri.ch/userfiles/file/dopudijobalereruf.pdfIn PDF document text
    • http://wienbildarchiv.com/upload_files/files/41047714117.pdfIn PDF document text
    • http://thuocnam.xyz/images/files/83712688584.pdfIn PDF document text
    • http://klubalfa.org/img/userfiles/file/85666448345.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_off0000e51c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE51C 18992 bytes
SHA-256: d2367e9d37dfc5fbad5baab255486a23194499e2b405625c501725218359cc85
font_01_sfnt_off00011705.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11705 10140 bytes
SHA-256: dafabb737da829f514dd4d5ed49f38a29b9e77474ad58ab5ac143d0d2de265fd
font_02_sfnt_off00012dbf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12DBF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1