Malicious PDF — malware analysis report

Static analysis result for SHA-256 856b84ce4af71b21…

MALICIOUS

PDF

84.6 KB Created: 2021-07-06 12:44:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: eacd0fd7db446a75dd33454fe0ad2adc SHA-1: 00ce5fccb71199dd826c9289e04b16f06a4be69d SHA-256: 856b84ce4af71b2112352452bb45c1ad64dc540b55b647d39586a5bec34b39b8
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous embedded URLs pointing to compromised websites and potentially disposable hosting, suggesting a phishing or malware distribution scheme. The presence of multiple PDF-specific heuristics related to URI and link farms further supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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 https://infrive.ru/uplcv?utm_term=do+employers+look+at+gpa PDF link annotation
    • http://gorisum.net/fckeditor/upload_file/file/sufusototidegowoxivixezut.pdfIn PDF document text
    • https://www.hediyevideo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075b178da733---konolidimazopuwisuvo.pdfIn PDF document text
    • http://atlantichomeportugal.com/wp-content/plugins/formcraft/file-upload/server/content/files/160797928dacd9---wifoxigisisavur.pdfIn PDF document text
    • http://droprint.my/home/ququ4923/public_html/userfiles/file/79207778441.pdfIn PDF document text
    • http://nuyewrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/e45f610485db2ce8341f52f42a1c3021/fudajunerasuluwuwexiwo.pdfIn PDF document text
    • http://odpadykj.cz/UserFiles/File/sobanofujomikebebe.pdfIn PDF document text
    • http://www.sunarozlem.com.tr/wp-content/plugins/super-forms/uploads/php/files/4hlec8rtitmchhb77gvpi18995/bufixebepikizojikazuregew.pdfIn PDF document text
    • https://hartwellcook.com/wp-content/plugins/super-forms/uploads/php/files/2a2e220b2e52742dfb4460f84bf8fdc1/kukixufakituredominepemiz.pdfIn PDF document text
    • https://40parables.com/wp-content/plugins/super-forms/uploads/php/files/b6e964de749be04f5363a97ee101c477/15241180343.pdfIn PDF document text
    • https://traveltokiev.com/wp-content/plugins/super-forms/uploads/php/files/qmceuliljpg4mcelooq60pa4l0/nagumefejep.pdfIn PDF document text
    • http://ac-kenigsberg.ru/files/file/99199073548.pdfIn PDF document text
    • http://e-skala.pl/userfiles/file/96414859710.pdfIn PDF document text
    • http://www.sunargrup.com.tr/wp-content/plugins/super-forms/uploads/php/files/243q0636dsgmcfk5r8rrq2rtb3/78001268810.pdfIn PDF document text
    • http://www.alborada.es/ckfinder/userfiles/files/93873315864.pdfIn PDF document text
    • https://avenirpourtous.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16073e9a58e342---wulut.pdfIn PDF document text
    • https://criteriacambio.com.br/wp-content/plugins/super-forms/uploads/php/files/4b0ht5gg311uur77fs6l7abkac/zilexofun.pdfIn PDF document text
    • http://www.fattyweng.com.sg/wp-content/plugins/formcraft/file-upload/server/content/files/1607b908d224dc---84713992580.pdfIn PDF document text
    • https://namhunglogistic.vn/site/files/vupamoz.pdfIn PDF document text
    • http://hilimall.ae/uploads/files/ketutiwudowomazujenif.pdfIn PDF document text
    • http://bjzjygj.com/fckeditor/editor/filemanager/connectors/php/userfiles/file/75413406951.pdfIn PDF document text
    • https://nezrenpin.com/calisma2/files/uploads/9179830647.pdfIn PDF document text
    • https://www.synergyheart2heart.team/wp-content/plugins/super-forms/uploads/php/files/gne8n2t3fdpm688qkodf46aj4h/pason.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_off0000e863.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE863 10604 bytes
SHA-256: d2a81e79b7adc855b8a51e14cf33aba6860f7a47cfc85969eb2dbfee314fc015
font_01_sfnt_off000100b6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100B6 17176 bytes
SHA-256: 8b24f95e698b072bf921d313748b7740f78e2f61f55c9a7a912bd82619531341
font_02_sfnt_off00012d10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12D10 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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