Malicious PDF — malware analysis report

Static analysis result for SHA-256 181637c51004e289…

MALICIOUS

PDF

74.8 KB Created: 2021-09-22 16:47:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 3b9c0b9e7c69695115b9690239a19ec4 SHA-1: 51d437b7360b21c39ca9bb33aa5205b29b64d4c3 SHA-256: 181637c51004e2893716636484a2b26c642cc8a3ec326036f872df7110264a35
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically indicating phishing and trojan behavior. It contains numerous external URIs and link farms pointing to compromised WordPress uploads and disposable hosting, suggesting an attempt to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, lacking readable content but reinforcing the malicious nature indicated by the heuristics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://catamma.ru/uplcv?utm_term=ppsspp+minecraft+download
    • https://durgabas.coop.np/ckfinder/userfiles/files/lojufumutaz.pdf
    • http://ventensis.lt/public/ckfinder/userfiles/files/nikolikawejewow.pdf
    • http://e-sportis.com/images/upload/galofuwoseroxolaluwesa.pdf
    • http://xn--80aadq3ae7aa5k.xn--p1ai/upload/file/39458594439.pdf
    • https://solelane.com/ckfinder/userfiles/files/24470258912.pdf
    • http://abnig.friendship-match.com/upload/files/80327625493.pdf
    • http://idrogastermoclima.it/Utentifile/FCKPage/file/zexunakagabu.pdf
    • https://webtechnocrats.com/upload/file/wukuba.pdf
    • https://webrobogo.hu/kepek/77841925233.pdf
    • https://www.pessin-location.fr/ckfinder/userfiles/files/xojusudesexuwaxejesasi.pdf
    • http://www.sunarpazarlama.com/wp-content/plugins/super-forms/uploads/php/files/0ado0sg9st7qn7bi3hma7t8ve6/lasenapakedipi.pdf
    • https://vasantviharproperties.com/userfiles/file/81078089930.pdf
    • http://sgyscom.com/upload_fck/file/2021-9-12/20210912114747235808.pdf
    • http://nebovsem.ru/app/webroot/files/files/piwujolebazuje.pdf
    • http://clinicaveterinariagussago.com/userfiles/files/36355061729.pdf
    • http://miyozenemeryville.com/uploads/files/67857959652.pdf
    • http://topmebli.com/content/xuploadimages/file/vozodimixefatematoxom.pdf
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/1614271d03585f---96256213026.pdf
    • https://www.kadinlarsitesi.org/wp-content/plugins/formcraft/file-upload/server/content/files/161427babc64c4---21387446560.pdf
    • https://inverpalmas.com/aym_image/files/17014198289.pdf
    • http://abimobiliare.pl/pliki/File/49751738598.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c338.bin
2781501d4598c09befbd0e72f7c0b4f4ef41c6e7a7cf23cb37b67ff4207c4ba9		 pdf-font-stream PDF embedded font (sfnt) at offset 0xC338 10868 bytes
font_01_sfnt_off0000dc5d.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDC5D 16792 bytes
font_02_sfnt_off0000f46f.bin
bf4cde94358657da1a6b318631a8d2196cf5dc2636c9887f3001d1d3f9d53ea1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF46F 16136 bytes

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