Malicious PDF — malware analysis report

Static analysis result for SHA-256 31fd901fd1fd53ce…

MALICIOUS

PDF

76.6 KB Created: 2021-07-21 08:18:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 9c9846cabeef1e645753d899b2e669b5 SHA-1: 3a4e5822a032eceea1bf5bd4c79171d0b3b0446a SHA-256: 31fd901fd1fd53cef13a925b0ab4e5b44baecc7eebcae32f44ae6d3cbb1e4d5c
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for executing malicious code. Heuristics indicate it is a link farm pointing to compromised WordPress upload storage and disposable hosting, suggesting a phishing or malware distribution lure. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://duonglaohanoi.com/userfiles/file/46070007396.pdf
    • https://hylyt.co/wp-content/plugins/super-forms/uploads/php/files/47312f8d07efe23e7680a571f725e70c/47021693255.pdf
    • http://bachtungcompany.com/upload/files/xerufimuzivaregazatipaki.pdf
    • http://cesishotel.lv/res/wysiwyg/file/wetivoxadijezogipuxo.pdf
    • https://avenirpourtous.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1606e793b99d5d---72596915396.pdf
    • https://www.cdscabling.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160ab13d150cf2---faxenizejisil.pdf
    • https://www.olympusnorge.no/wp-content/plugins/super-forms/uploads/php/files/d7g31k8omvrjgq4h9vi7l3jdhj/99992664631.pdf
    • http://rufullthrottle.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607380702e5eb---vigijuponokipefux.pdf
    • http://absolutelyneon.com/userfiles/file/tolipivixevobukugo.pdf
    • http://www.grundys.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160823b5a4f97d---bulidewem.pdf
    • http://chiari-web.com/ckfinder/optimist/files/likakuviporiluf.pdf
    • https://imahima.xyz/js/ckfinder/userfiles/files/76091772750.pdf
    • http://dijladentalcenter-qa.com/userfiles/file/bufexuset.pdf
    • http://hzqzg.com/d/files/veratafewofetaguwevupaka.pdf
    • http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608bee3d737ac---pudubukegi.pdf
    • http://gdbchurch.com/clients/43262/File/86933468963.pdf
    • https://pilotcenter.gr/wp-content/plugins/super-forms/uploads/php/files/lnda0cjdusdcokgvk0bfiuqpkt/zovubopowemege.pdf
    • http://nhhs78.org/clients/63854/File/15641467317.pdf
    • https://hopefor.today/wp-content/plugins/super-forms/uploads/php/files/897cdb7c09dd20f6bf97783ae6a3a316/80688967411.pdf
    • https://vrrc.heart.net.tw/ckfinder/ckfiles/files/jiguwasiruzufako.pdf
    • https://perfecthospitals.org/FCKeditor/file/maburenizemukovamej.pdf
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/16090a1d95b0c5---64071116013.pdf
    • http://www.medicalalliedtraining.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b5f1e20b7e9---ninalofasexutituvozudilut.pdf
    • https://fenicia.uy/fenicia.com.uy/uploads/files/77133528996.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=3.3+cm+to+mm
    • 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_off0000ccb7.bin
8b5728120e19475208afd6e6753695bc964c2d8e366d5dbaac9a7e5525d05cc5
pdf-font-stream PDF embedded font (sfnt) at offset 0xCCB7 16712 bytes
font_01_sfnt_off0000f84a.bin
ff76537aabd6c0a9e63a3355c8324f652616f8803be59f75a727874221478299
pdf-font-stream PDF embedded font (sfnt) at offset 0xF84A 9728 bytes
font_02_sfnt_off00010d89.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10D89 16792 bytes