Malicious PDF — malware analysis report

Static analysis result for SHA-256 4fa1899de8a3d933…

MALICIOUS

PDF

88.0 KB Created: 2021-09-10 18:43:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: f229064a5794c8c477b735c2a683f345 SHA-1: 217e4eee54b331932056e930e50f65f754327707 SHA-256: 4fa1899de8a3d9335baffe40326ce555f1a802e82fb1a6896b2f0fd5dd5e4599
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The file is detected as a malicious PDF by ClamAV and an ML classifier. It contains numerous embedded URLs pointing to various domains, many of which appear to be compromised or disposable hosting. The PDF structure is malformed, suggesting an attempt to exploit vulnerabilities or hide malicious content. The presence of external URIs and link farms indicates a likely phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://coretry.ru/uplcv?utm_term=fire+kirin+app+for+android PDF link annotation
    • http://sarkanyhajo.hu/files/file/25896947958.pdfIn PDF document text
    • https://savitravel.ro/ckfinder/userfiles/files/tolonataduvef.pdfIn PDF document text
    • http://lexen.ca/userfiles/files/25593318730.pdfIn PDF document text
    • http://sartoriaventurini.com/userfiles/files/41653878464.pdfIn PDF document text
    • http://itnetworkconsultingsf.com/helpdesk/app/webroot/img/userfiles/files/9352341929.pdfIn PDF document text
    • http://dpsnowodworze.pl/userfiles/file/mavubujukomemogeludig.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/1612efe0ade9e6---tojorevamadisodujigiw.pdfIn PDF document text
    • https://cairparavel.ro/app/webroot/files/userfiles/files/wulaxetawufikejil.pdfIn PDF document text
    • http://www.airportlimofortlauderdale.net/wp-content/plugins/formcraft/file-upload/server/content/files/16135d501e1161---48738019718.pdfIn PDF document text
    • http://vhshf.de/File/vifibovesemume.pdfIn PDF document text
    • http://silverk.ru/img/lib/file/70094100944.pdfIn PDF document text
    • http://varadimasszazs.hu/uploads/files/87864516677.pdfIn PDF document text
    • http://lezeckastenakosice.sk/upload/files/94514366818.pdfIn PDF document text
    • http://liweisteel.co.th/ckfinder/userfiles/files/jotedigikedovuti.pdfIn PDF document text
    • https://majubesar.com/contents/files/75436236317.pdfIn PDF document text
    • http://thedewakohchang.com/image/upload/File/5680808142.pdfIn PDF document text
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/1613931ef05881---57880624389.pdfIn PDF document text
    • http://yangs-ns.com/ckfinder/userfiles/files/20210904083651.pdfIn PDF document text
    • https://www.grecosalesinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/161317df6c62e3---zetexikiroko.pdfIn PDF document text
    • https://certifiedcollisionrepair.com/home/cert/public_html/ckfinder/userfiles/files/silejowe.pdfIn PDF document text
    • http://sewakendragroup.com/userfiles/file/42445266545.pdfIn PDF document text
    • https://norservis.info/files/files/benazoxeve.pdfIn PDF document text
    • http://chulatutoracademy.com/chulatutor/ckfinder/userfiles/files/90903854388.pdfIn PDF document text
    • https://abyway.lv/images/ck_images/files/sidabuzeta.pdfIn PDF document text
    • http://uniquehotelsolutions.com/files/others/nanetudire.pdfIn PDF document text
    • http://z500.si/files/zawenidozuxurus.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_off0000f41b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF41B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010c32.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C32 10248 bytes
SHA-256: 737b221348a6c9f9a72d22f67501a14457e7d01a8ce67ef503fabbd3dc64022e
font_02_sfnt_off0001233e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1233E 18256 bytes
SHA-256: 8d4a6991126164af2a7aea852f9f6b350b8c84baadb96b3aac138ac8fafff3ee

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