Malicious PDF — malware analysis report

Static analysis result for SHA-256 43c13067daf59b1b…

MALICIOUS

PDF

72.4 KB Created: 2021-09-01 23:45:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 25efa8c580a7724c47cabeab1f1faec8 SHA-1: 793ed0b1ede83ce960023cf0fd0bdc313d20734b SHA-256: 43c13067daf59b1baa61beb1b219d376c294c9569693c13ba7282bb57bdc4220
176 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it contains a link farm pointing to compromised WordPress uploads and other disposable hosting, suggesting it's designed to redirect users. The malformed stream length and duplicate object body indicate attempts to obfuscate malicious content, likely involving exploit code or JavaScript to facilitate further compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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=chat+pe+soya+tha+behnoi+mp3+song PDF link annotation
    • http://coimbrasoftware.hu/images/uploads/files/23086611612.pdfIn PDF document text
    • https://xn--64-mlcufjjaii0l.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/03cef5e9a099f5be506193d8943cd388/30038780429.pdfIn PDF document text
    • http://twilaw.com/files/files/18444017512.pdfIn PDF document text
    • http://sbairs.com/datas/files/gigovinu.pdfIn PDF document text
    • https://www.lenoir-elec.com/wp-content/plugins/super-forms/uploads/php/files/ea9ja51at7e0bp4js9mj1f1ee3/lalakojup.pdfIn PDF document text
    • http://www.jcca.co.in/wp-content/plugins/formcraft/file-upload/server/content/files/160824e3e8d45e---panugevezuzixovatazavu.pdfIn PDF document text
    • https://nobleanimalsanctuary.org/wp-content/plugins/super-forms/uploads/php/files/tmp/30174290064.pdfIn PDF document text
    • https://www.heainc.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6f5ae5952e---jaguxiwisa.pdfIn PDF document text
    • http://atthaya.com/file_media/file_image/file/pizurimujamirabebezud.pdfIn PDF document text
    • https://sharpconsulting.us/app/webroot/ckfinder/userfiles/files/72192995635.pdfIn PDF document text
    • http://reversetheclocknow.com/ckfinder/userfiles/files/94891776613.pdfIn PDF document text
    • http://fbchitchcock.org/clients/8/8b/8bdff38a390027835eb24981312b950c/File/nifinixivazinegikavupu.pdfIn PDF document text
    • http://tropo-design.com/ckfinder/userfiles/files/pulusesupe.pdfIn PDF document text
    • https://sv-fin.ru/wp-content/plugins/super-forms/uploads/php/files/f0b81995eed382ace6c437cfb2f4a7cc/83623476285.pdfIn PDF document text
    • https://earthideasawnings.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a559278441f---wadobenuwupinenumenodifa.pdfIn PDF document text
    • https://action-roofing.com/wp-content/plugins/super-forms/uploads/php/files/7b079246fcd11b5cb12a7ca21ff82e4c/35633453194.pdfIn PDF document text
    • https://www.rath-catering.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607c84b2a8c23---wubozijifewobemusojusir.pdfIn PDF document text
    • http://starma.pl/files/file/fewunemasi.pdfIn PDF document text
    • http://iltorg.ru/upload/file/pekazamanexogofowa.pdfIn PDF document text
    • https://nullemont.fr/nullemont/ckfinder/userfiles/files/30020908528.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_off0000b5cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB5CB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cddd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDDD 17496 bytes
SHA-256: 01e1e3a6548fa04054ea4783bc0997b633bf5b0c9559f92212b1c159f9674574
font_02_sfnt_off0000fb6d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB6D 11008 bytes
SHA-256: 87e7a8c181690e58609a49963e9e6a41332735e26d5e8facf4b0fea11ab6875d

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