Malicious PDF — malware analysis report

Static analysis result for SHA-256 28253730e8c57137…

MALICIOUS

PDF

91.1 KB Created: 2021-08-12 07:56:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 45d3ccac22acf0e3d6b8648e8ce86d72 SHA-1: e2bd45e9493fbf75c8bd85feed0358e7ab483fc0 SHA-256: 28253730e8c57137a218a2bd28c89402a0115c095ed7ff7582c5d9c868d55946
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs that form a link farm, pointing to various domains, some of which are hosted on compromised CMS uploads. The primary purpose appears to be directing users to potentially malicious external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://worldcar.jp/userfiles/files/81565517099.pdf
    • https://waroproject.com/file/40665380054.pdf
    • https://festival.bg/fckeditorfiles/file/61327520079.pdf
    • https://cokhivietuc.com/img-vietuc/files/31326634799.pdf
    • https://www.kbstephens.com/wp-content/plugins/super-forms/uploads/php/files/c39a0203ae1e019f4780f455a2e2e5c4/berolutatoxezufevalo.pdf
    • http://neoneofytou.com/ckfinder/userfiles/files/48435825589.pdf
    • http://maxitelt.no/wp-content/plugins/formcraft/file-upload/server/content/files/1609f776be1dff---pidifiruvolorul.pdf
    • https://earplighting.com/wp-content/plugins/super-forms/uploads/php/files/a60d712a458b015506d91c6791e1ec08/87266227441.pdf
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/jkphutrdn32e5kdopq7i56j996/74971355681.pdf
    • https://jakspravnenapsa.cz/userfiles/file/rodatonedozalikuvuv.pdf
    • https://aguiapromocional.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16094ddc34fead---20198428688.pdf
    • http://myucmas.com/userfiles/file/revasumen.pdf
    • http://kuresi-kaitori.com/upload/content_pic/files/9505592340.pdf
    • http://biogenetec.tw/image/files/20210802_012118.pdf
    • https://engravestone.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b0fffb82b1---xedapenopate.pdf
    • http://www.webtony.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606ffee802c42---81770213641.pdf
    • https://www.penyembuhanholistikreiki.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d2b1a1e6ab3---11161926309.pdf
    • https://free-spirit-city.eu/uploads/wysiwyg/files/4870223191.pdf
    • http://micronforgacsolo.hu/UserFiles/file/24243385617.pdf
    • http://wenxuezj.com/images/File/10553201797.pdf
    • https://noble-worldwide.com/wp-content/plugins/super-forms/uploads/php/files/84e1db4a64fd0f74f2df813dff057b3a/34517909828.pdf
    • http://nousgarage.com/userfiles/file/45006620891.pdf
    • https://www.cedicar.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610701d423304---58670854058.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=multiplicaci%C3%B3n+de+fracciones+algebraicas+ejercicios+resueltos+pdf
    • http://kioskcondoweb.wpengine.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c1580becfd---desar.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_off0000f6ab.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF6AB 16792 bytes
font_01_sfnt_off00010ec2.bin
4fdb5a61ba1e3a0819150428974f38087808b15746c40295cbb33c0952cad708
pdf-font-stream PDF embedded font (sfnt) at offset 0x10EC2 11296 bytes
font_02_sfnt_off000128ba.bin
4adb44af44a4273b130349b7bdd448b8359c7e4b0c1715425d96b2d9061b4a8c
pdf-font-stream PDF embedded font (sfnt) at offset 0x128BA 18988 bytes