Malicious PDF — malware analysis report

Static analysis result for SHA-256 843da35b2f4906d1…

MALICIOUS

PDF

71.1 KB Created: 2021-09-13 21:00:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 8302e98ab997b4d4322236fa17391afd SHA-1: 5fae2cb2319cd33cb161dd3e81a01e5c39d41991 SHA-256: 843da35b2f4906d143869d29729b6f6000d30bdbb44a8fdf148bb3edc9c9ebc2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by multiple heuristics and a machine learning classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, suggesting a link farm designed to redirect users. The presence of PDF-specific heuristics like 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this. While no scripts were explicitly extracted, the nature of the URLs and the overall detection suggests a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 6

  • 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.
  • 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=mrna+codon+example PDF link annotation
    • https://krzczonowice.pl/gfx/file/58401760658.pdfIn PDF document text
    • http://unsersohn.ch/images/file/vaporelezi.pdfIn PDF document text
    • http://szao-spb.ru/images/news/file/govepegosufurodibavoj.pdfIn PDF document text
    • https://pierreseche.fr/userfiles/file/25790957669.pdfIn PDF document text
    • http://xn--80aer5aza.xn---42-5cdakyymnnb9ake1az.xn--p1ai/ckfinder/userfiles/files/tukatujikizirazobite.pdfIn PDF document text
    • https://autoroman-service.ro/imagini_ws/53326580047.pdfIn PDF document text
    • http://samocvet.org/foto/ck/files/11552140496.pdfIn PDF document text
    • https://noursportevents.com/wheelmarine/userfiles/file/mosedisuvidorojuzes.pdfIn PDF document text
    • https://www.spoton.pet/wp-content/plugins/super-forms/uploads/php/files/3jf34ggoe0a0i9u9v656umag9l/gulejebofinogojoliz.pdfIn PDF document text
    • http://www.uc-kushiro.net/images/library/File/vivetuwoduvuwomama.pdfIn PDF document text
    • https://spirit-legend-enterprises.com/webroot/editor-uploads/files/67661009496.pdfIn PDF document text
    • http://skontrolsengineering.com/file_media/file_image/file/sebeneresafovuxuvigite.pdfIn PDF document text
    • https://imagebeaute.fr/userfiles/file/livifezesewufujewelaroloz.pdfIn PDF document text
    • http://softtox.com/new/userfiles/file/ranakidikegeka.pdfIn PDF document text
    • https://swift-tw.com/lcc/upload/files/86009864521.pdfIn PDF document text
    • http://retroldn.com/userfiles/file/zezupo.pdfIn PDF document text
    • http://krzeptowski.pl/file/30358288848.pdfIn PDF document text
    • http://www.jhannahs.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612ec61460210---dinex.pdfIn PDF document text
    • https://eecpowerindia.com/codelibrary/ckeditor/ckfinder/userfiles/files/lizabidixexatajobag.pdfIn PDF document text
    • https://egokituz.org/files/galeria/files/90377483526.pdfIn PDF document text
    • https://choiceenergynetwork.com/wp-content/plugins/super-forms/uploads/php/files/e315ceeb2bed97b976b9a3df5dd78927/suxekafowuzelivinoke.pdfIn PDF document text
    • http://arqing.es/ckfinder/userfiles/files/38634521873.pdfIn PDF document text
    • https://frontiermyanmar.com/sites/all/libraries/ckfinder/userfiles/files/fowev.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_off0000b74a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB74A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cf61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF61 10412 bytes
SHA-256: 24e94274376422f7838f5b98a7c8b48c9eab9f8801defee7dd41edc24119a7a8
font_02_sfnt_off0000e6ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6EA 15584 bytes
SHA-256: b8d8a09cec2574e99ffa89129624f5a55e5e7da5dd148aff4d285c662738d4f9

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