Malicious PDF — malware analysis report

Static analysis result for SHA-256 f899315ac3e56e90…

MALICIOUS

PDF

81.4 KB Created: 2021-09-16 18:15:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 80ff9fddf25b214acbcfab4e9716d70b SHA-1: a059a13526e0983e09fc7d2fa6a096273448d432 SHA-256: f899315ac3e56e90779f92c15c279113c5204b88e90029bb4663eeac6eacafc7
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, one of which is hosted on disposable infrastructure. The document body is heavily obfuscated and appears to be metadata rather than user-readable content, suggesting the primary purpose is to host malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 http://chukguwang.com/files/fckeditor/file/34690544165.pdf In PDF document text
    • http://stapper.de/sites/default/files/userfilesfile/73094893249.pdfIn PDF document text
    • http://idealhca.com/admin/images/file/nebaxivule.pdfIn PDF document text
    • https://ud-hobby.com/images/Upload/file/53335759241.pdfIn PDF document text
    • http://servicedental.it/userfiles/files/pogejikigijimomoxa.pdfIn PDF document text
    • http://ambulatorioveterinariocamali.com/userfiles/files/36464746307.pdfIn PDF document text
    • http://www.physedu.in/newsite/userfiles/files/dovubut.pdfIn PDF document text
    • https://nuregio.de/wp-content/plugins/formcraft/file-upload/server/content/files/1614356bfe80a6---tetuwivuluzuvofukaxewo.pdfIn PDF document text
    • http://carrozzeriardue.it/userfiles/files/40504562813.pdfIn PDF document text
    • https://pensionradvanice.cz/res/file/xafugutuxa.pdfIn PDF document text
    • http://heryeryesil.com/resimlerfiles/31146440630.pdfIn PDF document text
    • http://prestopc.it/upload/file/6660520987.pdfIn PDF document text
    • http://wawa757.com/uploads/files/begovukukumelusalugorudo.pdfIn PDF document text
    • http://monticellotownship.org/userfiles/file/renedafefuderug.pdfIn PDF document text
    • http://wienbildarchiv.com/upload_files/files/fulomazutevezuxegume.pdfIn PDF document text
    • https://zaragozadenoche.es/upload/files/kiwekafojugelizowumupi.pdfIn PDF document text
    • http://slxiang.com/v15/Upload/file/20219152154552243.pdfIn PDF document text
    • https://duvanco.be/docs/files/zenovarojoda.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=how+to+download+as+pdf+on+macPDF link annotation
    • http://zs.tom.ru/jsplugins/ckfinder/userfiles/files/begujifupubu.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_off0000daac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAAC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f2c3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2C3 10532 bytes
SHA-256: 3a30f77055124eed48aeb43ed5cc04c82f2efbd3ece16a524c2a25b502b50bd4
font_02_sfnt_off00010acd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10ACD 17572 bytes
SHA-256: 4d885cf2f5f5edc249271123e7da1b8856d19392efa2ab09400e8c1c100227c0

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