Malicious PDF — malware analysis report

Static analysis result for SHA-256 4cb87bb377b62c29…

MALICIOUS

PDF

73.2 KB Created: 2021-09-05 22:47:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 8784bb9efc31b1a87a2defd0107f75ca SHA-1: 2e4d2650f6f7b7edd3d5084248080c401a9ae07f SHA-256: 4cb87bb377b62c2948b2ebcf690af88fcf78d91db243ca9631252e3be2d4cac5
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous embedded URLs that point to various websites, many of which appear to be compromised or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. The presence of link farm heuristics suggests the primary purpose is to redirect users to external, potentially harmful, content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

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://laborke.ru/uplcv?utm_term=ayurvedam+telugu+pdf PDF link annotation
    • https://patriot.ch/wp-content/plugins/super-forms/uploads/php/files/keq5l6j8f43iu2qk9bp1u5jng2/81197074625.pdfIn PDF document text
    • https://www.sterlingsez.com/ckfinder/userfiles/files/pofafevelobe.pdfIn PDF document text
    • https://www.coconutlodge.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d470adf44d---bufafokapu.pdfIn PDF document text
    • https://schmitz.cz/res/file/voravi.pdfIn PDF document text
    • http://istihdamhaberleri.com/upload/ckfinder/files/wokir.pdfIn PDF document text
    • http://tnshoppingbag.com/upfiles/file/97947795769.pdfIn PDF document text
    • http://mayamalay.com/clients/874202/File/65265373035.pdfIn PDF document text
    • http://studiodugnani.it/userfiles/files/73283262314.pdfIn PDF document text
    • http://www.greddy.com/admin/common/ckfinder/userfiles/File/vanugebom.pdfIn PDF document text
    • https://next-engineering.com/userfiles/files/52265593006.pdfIn PDF document text
    • http://teaterskolen-efteruddannelsen.dk/ckfinder/userfiles/files/7106645793.pdfIn PDF document text
    • https://brunoamaranti.it/wp-content/plugins/super-forms/uploads/php/files/c13aq7o953j6o1g3ikh6s6ir71/zukokirusopex.pdfIn PDF document text
    • http://tsg-vaganovskoe.ru/ckfinder/userfiles/files/5248106352.pdfIn PDF document text
    • https://leicht-spb.ru/wp-content/plugins/super-forms/uploads/php/files/08a73ac89e45cbc74e9608577a9d6b61/11148774293.pdfIn PDF document text
    • http://wabasnb.com/files/fckeditor/file/135206965461178f477de38.pdfIn PDF document text
    • http://majorpropertygroup.com/userfiles/files/83644381950.pdfIn PDF document text
    • http://shreejians.com/userfiles/file/gerimuja.pdfIn PDF document text
    • http://hcbarrett.com/user_area/file/pivagevupewagelare.pdfIn PDF document text
    • http://global-poseg.com/wp-content/plugins/formcraft/file-upload/server/content/files/160773ce0a49d6---xumimux.pdfIn PDF document text
    • https://luyenthitoeic.info/userfiles/file/52558426787.pdfIn PDF document text
    • https://provisionsinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a3d04f422d5---gexunokifisililiviguro.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_off0000bbb3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBBB3 17084 bytes
SHA-256: e168318f03a3436a80d04881ab7301e273092fddece8a3a2505fc43782a95e0b
font_01_sfnt_off0000e7af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE7AF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000ffc6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFC6 10620 bytes
SHA-256: 079fccd7e0a83030c75e7e2e703b9e83d551f2906c887558694a40457c9457c9