Malicious PDF — malware analysis report

Static analysis result for SHA-256 1f31dbbcb247d5c6…

MALICIOUS

PDF

88.8 KB Created: 2021-09-11 05:48:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-29
MD5: 024be4e6a497000c482929cac6c7794c SHA-1: 4c33a35ecec3b6f1b279b7301e55f40abcb34ff1 SHA-256: 1f31dbbcb247d5c67c615425927619ca2407807e463b2847873af700b3e4cc0f
174 Risk Score

Malware Insights

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

The PDF document exhibits characteristics of a phishing lure, specifically prompting the user to install a browser extension or update to view content. This is supported by the 'SE_BROWSER_INSTALL_LURE' heuristic. The document also contains numerous external URIs, including one pointing to a potential download URL, indicating an attempt to deliver a secondary payload. The ML classifier and ClamAV detection further confirm its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://synerhu.ru/uplcv?utm_term=chrome+cracked+apk PDF link annotation
    • http://dlshixiang.com.cn/ckfinder/userfiles/files/42521906197.pdfIn PDF document text
    • https://onhimalayas.com/ckfinder/userfiles/files/33323492025.pdfIn PDF document text
    • http://kes.org/upload/editor/files/9872724355.pdfIn PDF document text
    • https://www.taxiserviceh24.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613877df67749---zuluribizedeganadoka.pdfIn PDF document text
    • http://yeditepegumruk.com/userfiles/52592481014.pdfIn PDF document text
    • https://ecableapp.com/FCKeditor/FCKimgUpload/file/27861775098.pdfIn PDF document text
    • https://bongkartuantakur.com/contents/files/17966186058.pdfIn PDF document text
    • https://inunekocp.jp/mailmagazine/upload/files/sesarirufaj.pdfIn PDF document text
    • http://rlmlaw.com/images/edit_images/file/85048171927.pdfIn PDF document text
    • http://cluboutletmoto.net/campannas/file/23256132056.pdfIn PDF document text
    • http://wowbond.com/upload/Fckeditor/file/nilenesiratuzalimubiwidu.pdfIn PDF document text
    • http://divodizain.ru/ckfinder/userfiles/files/33393210139.pdfIn PDF document text
    • http://babyindex.nl/images/uploads/77157537653.pdfIn PDF document text
    • https://avantkart.com/wp-content/plugins/super-forms/uploads/php/files/em084jlp065oo290h29ivvmcnb/91870826586.pdfIn PDF document text
    • http://daltan.hu/userfiles/file/46374179169.pdfIn PDF document text
    • http://longruiglass.com/ckfinder/userfiles/files/20210909_124843.pdfIn PDF document text
    • https://fidelishospice.com/ckfinder/userfiles/files/nolutenaxujilod.pdfIn PDF document text
    • http://salukool.ee/upload/userfiles/file/96525328516.pdfIn PDF document text
    • http://top1np.com/ckfinder/userfiles/files/mefidebajud.pdfIn PDF document text
    • https://erdenet.mn/userfiles/file/12393996142.pdfIn PDF document text
    • https://ciela13.leaddeehub.com/userfiles/files/53313338090.pdfIn PDF document text
    • http://hairfibers24.com/upload/file/33797184386.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_off0000f5cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5CF 10392 bytes
SHA-256: 86337fdabf4a2e3929887f1d3a0a37b06d6a6163564e6561f55597bd120abe52
font_01_sfnt_off00010d51.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D51 18596 bytes
SHA-256: 2c728600c17dd62858a17bd3eba7964443de01c5bdd888af1e539cd12fabc35f
font_02_sfnt_off00013d9b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13D9B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1