Malicious PDF — malware analysis report

Static analysis result for SHA-256 244b2ab88850542b…

MALICIOUS

PDF

104.3 KB Created: 2021-06-25 12:18:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 5e72faeef21aab2f9b34daacb8dcc530 SHA-1: ce17e4b967b3bb3a22437b70a6f8a9b548ce1e98 SHA-256: 244b2ab88850542b20072b573802af1049feb229efd74c8e8caae32673614034
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many pointing to compromised WordPress sites and disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of PDF-specific heuristics like PDF_URI and PDF_SEO_DISPOSABLE_LINK_FARM further supports the attack pattern of luring users through deceptive links within the document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Clickable URI points to raw IP address medium PDF_URI_IP_LITERAL
    PDF contains a clickable HTTP(S) action whose host is a literal IPv4 address. Legitimate documents normally link to named domains; raw-IP destinations are common in disposable phishing and malware-delivery infrastructure.
  • 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://chcial.ru/uplcv?utm_term=accounting+information+system+thesis+pdf
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/b6nfpsguc7f45tl5s1g8h1g44v/82131592231.pdf
    • https://nuregio.de/wp-content/plugins/formcraft/file-upload/server/content/files/160aabe85d6367---71063317.pdf
    • http://staresecurity.com/userfiles/file/40168842039.pdf
    • http://www.risingstars.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160712a2b3db9d---bisikivogar.pdf
    • http://przychodnia-felinskiego.pl/uploads/editor/file/fanukeliv.pdf
    • http://m-camper.ru/ckfinder/userfiles/files/52048887992.pdf
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b5d643c4ff.pdf
    • http://hutergroup.de/userfiles/file/kipaxakafemuwo.pdf
    • http://104.156.58.56/~web2inbox/wp-content/plugins/formcraft/file-upload/server/content/files/160c8fbd022c7c---koxida.pdf
    • https://www.wikiwebagency.it/wp-content/plugins/super-forms/uploads/php/files/796e3284a391add6aa4583ab130c94ba/69025081189.pdf
    • https://www.lamuccacompany.com/wp-content/plugins/super-forms/uploads/php/files/9564e7d714e5362463a7ad4f686866b5/letubasoripalixe.pdf
    • http://zbraneklapka.cz/ckfinder/userfiles/files/visajumorejerepa.pdf
    • https://www.hontoys.com.au/wp-content/plugins/super-forms/uploads/php/files/jqnqsim7qfigm2j3gaps819imf/55275266181.pdf
    • http://fullcolorspandoeken.nl/userfiles/file/joguxobal.pdf
    • http://oio.cn/uploadfiles/files/57044368684.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_off000134e6.bin
53eaac38e3d860160a2e24b1b863ceff0495ca5fd0f99d7208a96eb4101ac9ee
pdf-font-stream PDF embedded font (sfnt) at offset 0x134E6 11216 bytes
font_01_sfnt_off00014ee5.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x14EE5 16792 bytes
font_02_sfnt_off000166f7.bin
0c852b0f8b00218d5c6600b5ab9072859d53cc68e5f15ba2daa26b5387930510
pdf-font-stream PDF embedded font (sfnt) at offset 0x166F7 17268 bytes