Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1b0c3fb9457c307…

MALICIOUS

PDF

70.4 KB Created: 2021-09-06 18:09:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 38482c62a7fce8f262c6c469905c201b SHA-1: a91aaf47c445d4e93ec2b65b6455a1cd3d1747da SHA-256: b1b0c3fb9457c307c78aff9963b5a1b851a89d871de57ef4816de90db820f9da
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Numerous heuristics point to the PDF being part of a link farm hosted on compromised WordPress sites and disposable domains, suggesting it's used to redirect users to malicious content. The embedded URLs, such as 'https://krisoc.ru/uplcv?utm_term=implementasi+keperawatan+pdf', are likely part of a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9986

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://krisoc.ru/uplcv?utm_term=implementasi+keperawatan+pdf PDF link annotation
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160bb7c3499f2d---sikuxemonitiginipekit.pdfIn PDF document text
    • http://lctrading-gmbh.com/ckfinder/userfiles/files/49266634212.pdfIn PDF document text
    • https://china-glass-mosaic.com/userfiles/files/20210627_170614.pdfIn PDF document text
    • https://boldvision.tv/wp-content/plugins/formcraft/file-upload/server/content/files/16076057995730---zuvaxogedozuwad.pdfIn PDF document text
    • http://timeyear-v.com/userfiles/file/25438532331.pdfIn PDF document text
    • https://alansglobalservices.com/ckfinder/userfiles/files/zamewis.pdfIn PDF document text
    • http://chocolatycakes.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076c4f91401c---19884432060.pdfIn PDF document text
    • http://www.hkwebdesign.com.hk/wp-content/plugins/formcraft/file-upload/server/content/files/160d648a3ccfdb---52257321740.pdfIn PDF document text
    • http://keyflounge.nl/userfiles/file/63054748556.pdfIn PDF document text
    • https://autonoleggioassereto.com/file/48907413519.pdfIn PDF document text
    • http://enjoybowlramenandpoke.com/uploads/files/kodukaridezuxil.pdfIn PDF document text
    • http://www.investinwielkopolska.pl/application/lib/ckfinder/userfiles/files/segapaduj.pdfIn PDF document text
    • http://valdhans.cz/userfiles/file/37968772571.pdfIn PDF document text
    • https://www.mercedesbenzofaustinservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/16088ffc987ced---79876026832.pdfIn PDF document text
    • https://frontiersneurophotonics.org/wp-content/plugins/formcraft/file-upload/server/content/files/1/160986380c2b72---pemexori.pdfIn PDF document text
    • https://www.rekalibracija.com/wp-content/plugins/super-forms/uploads/php/files/b511d921506db3b4bb4fe1ee904bd804/razitalabakifawabebemibaf.pdfIn PDF document text
    • http://trackeg.com/en/wp-content/plugins/formcraft/file-upload/server/content/files/160d913e21e8de---14711803718.pdfIn PDF document text
    • http://www.playerclub.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160a02d319fe4c---magurijazunenofevimidikin.pdfIn PDF document text
    • http://mega-stainlesssteel.com/uploads/image/files/4837668585.pdfIn PDF document text
    • http://fitnessklub-impuls.pl/uploads/assets/file/goworirelog.pdfIn PDF document text
    • http://littlepearlbooks.in/data/eimages/file/5199788517.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_off0000b56f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB56F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cd81.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD81 15088 bytes
SHA-256: 92a3d98cfe54239482af340e5561f7d354f3cfc8a84be7141ca262d232b6a3b1
font_02_sfnt_off0000f383.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF383 10668 bytes
SHA-256: c39610e090e79ecc487e909c70cac6b0ab7a4b68f5d7fdc803199c2b9edb05ec

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