Malicious PDF — malware analysis report

Static analysis result for SHA-256 b99aaa423eb3718c…

MALICIOUS

PDF

125.8 KB Created: 2021-06-28 19:56:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: d958dbfa3e4c3f1901b8c56ebd1107b3 SHA-1: 80327e414f2faadbd6b98633dc30e8025c54c191 SHA-256: b99aaa423eb3718c6e199ab2ea983b0168b39432faff67fd912851490daf2a22
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, directing users to multiple compromised websites and disposable hosting domains. The presence of external URIs and the nature of the detected heuristics strongly suggest a phishing or malware distribution scheme, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9969

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://irlanc.ru/uplcv?utm_term=machine+learning+a+bayesian+and+optimization+perspective+2nd+edition+pdf
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606e3650484bf---gotowuzesujelegumefofu.pdf
    • http://ebslang.net/_UploadFile/Images/file/mafudifaz.pdf
    • https://www.energetisch-therapeut-estie.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160897cb9e2ef0---zivexaz.pdf
    • http://shophouse.info/images/files/vupekoranet.pdf
    • https://www.dentaltaxpros.com/wp-content/plugins/super-forms/uploads/php/files/acb55b3bcf22cba7bdbbb44ff2569cae/latufumulezujukupifana.pdf
    • https://myphi.biz/nbloom/fckuploads/file/fumeturesebel.pdf
    • http://baaningdoi.com/file_media/file_image/file/44597544824.pdf
    • http://auburn-companies.com/userfiles/files/jilozakajafagalunit.pdf
    • http://careerhack.net/wp-content/plugins/formcraft/file-upload/server/content/files/1607f5569c6ea9---xokogonibusibujube.pdf
    • http://www.medical-psychology.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160987110cb249---55083518238.pdf
    • http://www.misshandicap.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160a9f1015ec56---18258337028.pdf
    • http://www.highlandmetals.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160800d888670a---7199627788.pdf
    • https://www.energetisch-therapeut-estie.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160c0577b26e9f---dusutugolav.pdf
    • http://beijingbeat.com/contents//files/72752435517.pdf
    • http://www.deopendeur.org/imgUser/file/67846679754.pdf
    • http://www.everhouse.lt/wp-content/plugins/formcraft/file-upload/server/content/files/1608448433627c---begesoze.pdf
    • http://www.rebranded.tv/wp-content/plugins/formcraft/file-upload/server/content/files/160a169cb34852---kaxawotegapug.pdf
    • http://sgyscom.com/upload_fck/file/2021-6-19/20210619131416741364.pdf
    • https://limpjet.com.br/wp-content/plugins/super-forms/uploads/php/files/bd93b6c1df22080fec22b985744d1e53/pozemosuvetisanefo.pdf
    • http://gospelinamerica.com/clients/874377/File/2618835530.pdf
    • https://inchiriereelicoptere.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1606cd1650673a---bejafesipudevamizomazuf.pdf
    • http://www.predoisiasociatii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160bc988255e26---56095884908.pdf
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c8761c1cb3c---dodub.pdf
    • https://earthchartercities.org/wp-content/plugins/formcraft/file-upload/server/content/files/16070f3016ab91---lenorofof.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00017bb8.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x17BB8 16792 bytes
font_01_sfnt_off000193cf.bin
18ebba1432908ce6359ea44ab5e0f3173168b3b59f3852790566870e28523b27
pdf-font-stream PDF embedded font (sfnt) at offset 0x193CF 11560 bytes
font_02_sfnt_off0001aeb7.bin
2ce68f4adc99a9dbae2445f3052915be440918dc7cc2ad315c11b2fac3843716
pdf-font-stream PDF embedded font (sfnt) at offset 0x1AEB7 21552 bytes