Malicious PDF — malware analysis report

Static analysis result for SHA-256 83db555dd792b70b…

MALICIOUS

PDF

84.4 KB Created: 2021-09-17 14:29:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: ef403071e77d591124d2db1fc08b8bfb SHA-1: 745cc416fea55f20e135d2f029c63f756645075e SHA-256: 83db555dd792b70b2d8e467402ae74390cc4b70f6a8edf22aa0df42181e4ada9
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 contains numerous external URIs and links to compromised CMS uploads, suggesting it's part of a link farm designed to redirect users to malicious sites. The presence of these links and the PDF structure strongly suggest a phishing or malware distribution campaign, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://medvor.ru/uplcv?utm_term=where+to+find+alarm+on+android PDF link annotation
    • http://premiumresourcing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134da531613b---48285121557.pdfIn PDF document text
    • http://31kouqiang.com/userfiles/file/1630651893.pdfIn PDF document text
    • http://www.uds-myanmar.com/image/upload/File/20032448063.pdfIn PDF document text
    • http://compie.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613006a389ff7---50453946567.pdfIn PDF document text
    • https://cissud.eu/uploads/ck_editor/files/bimudajatadavafum.pdfIn PDF document text
    • https://vegas-shop.net/uploads/files/ketelu.pdfIn PDF document text
    • http://nickels.design/ckfinder/userfiles/files/jamarujona.pdfIn PDF document text
    • https://www.americanapi.com/wp-content/plugins/formcraft/file-upload/server/content/files/161380be6cf3ed---88204874740.pdfIn PDF document text
    • http://holdemigny.fr/ckfinder/userfiles/files/11402662324.pdfIn PDF document text
    • https://esvigo.com/upload/files/15322891916.pdfIn PDF document text
    • http://bmcnx.com/userfiles/file/39197970855.pdfIn PDF document text
    • https://inprovitmexico.com/ckfinder/userfiles/files/15810925749.pdfIn PDF document text
    • http://karaokejdi.com/ckfinder/core/connector/php/upload/files/sorafawuv.pdfIn PDF document text
    • http://lsphc.com/userfiles/file///72672498975.pdfIn PDF document text
    • https://peptidturkiye.com/ckfinder/userfiles/files/rakobudetaxolekukusagof.pdfIn PDF document text
    • https://afritransport.com/app/webroot/files/file/zukidirezomegib.pdfIn PDF document text
    • http://cana.vn/uploads/userfiles/file/60013119210.pdfIn PDF document text
    • http://autosoftware.company/autoresponders_images/files/90328155590.pdfIn PDF document text
    • https://monyetmesum.com/contents/files/wunezuzejopok.pdfIn PDF document text
    • http://hyunsin.net/userfiles/file/nokirinabuxus.pdfIn PDF document text
    • http://quartierdete.fr/uploads/fckeditor/file/4598378992.pdfIn PDF document text
    • https://billionbosses.com/ckfinder/userfiles/files/49486995014.pdfIn PDF document text
    • http://gamjagolla.com/uploads/files/vinenifosedifojijako.pdfIn PDF document text
    • https://hondaotohaiphong.vn/upload/files/30732224925.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_off0000e4c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4C1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fcd3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCD3 18160 bytes
SHA-256: 366f5ab80ae29196ab2189d443d71ecfb4bc39ebf7cabf0f06f49a38a44378a9
font_02_sfnt_off00012cce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12CCE 10444 bytes
SHA-256: e263143608b291481009f49cef14bdb861278d1f623afa405bf7d96a1355c8fe