Malicious PDF — malware analysis report

Static analysis result for SHA-256 af589e75e54975a6…

MALICIOUS

PDF

70.6 KB Created: 2021-09-18 16:59:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 82cdf012848bc13afca01df0920c1330 SHA-1: 8e63efbf925b64fd76fddc4bd32804793752f0e8 SHA-256: af589e75e54975a612c430fabc5192b496dd1a95522c6a61bc829a32b58b92db
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating a malformed exploit stream and a link farm on disposable hosting. The PDF contains numerous external URIs, with one pointing to a URL that appears to be part of a redirection chain for downloading an APK, suggesting a phishing or malware distribution attempt. No scripts were extracted, but the PDF structure itself is indicative of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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
  • 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.
  • 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://www.edmcenter.xyz/ckfinder/userfiles/files/40504462014.pdf In PDF document text
    • http://www.saito-ken.jp/userdata/file/kevamevokafilapofolami.pdfIn PDF document text
    • https://rodolphe-blanchet.fr/Rodolphe/fckeditor/file/vuxomemuka.pdfIn PDF document text
    • http://pate4me.com/userfiles/file/bubabed.pdfIn PDF document text
    • https://yaslibakicisi.net/userfiles/file/muginunorozi.pdfIn PDF document text
    • http://radis-rrl.ru/userfiles/image/93635669482.pdfIn PDF document text
    • http://bienbao.net/uploads/files/xerevi.pdfIn PDF document text
    • https://mavachhaiphong.com/upload/files/44684131758.pdfIn PDF document text
    • https://ce-mi.pl/uploads/userfiles/files/waxukofep.pdfIn PDF document text
    • https://pcparts.fr/ckfinder/userfiles/files/14346840424.pdfIn PDF document text
    • http://malerbetrieb-malanders.de/Webseite/pics/fotos/1/file/zinov.pdfIn PDF document text
    • https://stabiactiv.com/userfiles/file/fadipexupipozosuxa.pdfIn PDF document text
    • http://nextgenship.net/upload/file/20210906163096901776.pdfIn PDF document text
    • https://milorem-service.ru/userfiles/file/gawepipominefefog.pdfIn PDF document text
    • http://narcisse.sk/editor_uploads/files/41731292302.pdfIn PDF document text
    • https://alasclub.gr/neuro/ckfinder/userfiles/files/15299986007.pdfIn PDF document text
    • https://www.limratechnologies.net/wp-content/plugins/formcraft/file-upload/server/content/files/161384345d6b08---mubimig.pdfIn PDF document text
    • http://xn--2osv9pt2jfpt.com/uploadfiles/files/zoxujifetogugidugizowanu.pdfIn PDF document text
    • https://euroroma-bg.org/files/file/38220288492.pdfIn PDF document text
    • https://www.elektrobetrieb-scholz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613e236bc9530---busave.pdfIn PDF document text
    • http://thienanglass.vn/upload/files/95819028402.pdfIn PDF document text
    • https://gamma-electronics-eg.com/userfiles/files/17083465625.pdfIn PDF document text
    • https://renebeumer.nl/userfiles/file/1022103416.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=aeroplane+game+download+apkPDF link annotation
    • 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_off0000b7a8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB7A8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cfba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCFBA 14916 bytes
SHA-256: b321b07b6c995b71d919cdeb511e42e3207ce6335d835b52776368e168cacd38
font_02_sfnt_off0000f577.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF577 10536 bytes
SHA-256: f36d2275261cd173d6e6b4d006df4f7e17f264a3dcf174347f3831f40a1ef680