Malicious PDF — malware analysis report

Static analysis result for SHA-256 a64b4be69e342dac…

MALICIOUS

PDF

78.1 KB Created: 2021-09-28 11:56:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 2b9c33c5876926b00cec02fea1bb657d SHA-1: 0021cca0df4742612a584a6e4fdd9a4ffb4b29be SHA-256: a64b4be69e342dac5cad2ddfd32a1f653aa2e88f8f9e5527eb7d9b5eda58308b
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was flagged by ML classifiers and ClamAV as malicious, with specific heuristics indicating it functions as a link farm on disposable hosting. The embedded URLs, such as 'https://infrive.ru/uplcv?utm_term=android+apps+apk+downloader', likely lead to phishing or malware distribution sites. Although no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with phishing lures.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://infrive.ru/uplcv?utm_term=android+apps+apk+downloader
    • http://exima.kr/userData/board/file/77161302733.pdf
    • https://www.miotsukushi.or.jp/system/ckfinder/userfiles/files/juwerobiduwadenadizox.pdf
    • https://tahuacoop.com/cms_gpadmin2015/sgi_userfiles/userfiles/files/90590903967.pdf
    • http://hospitalityroyal.com/upload_files/file/37778638335.pdf
    • http://fteq.ru/files/file/tomebonevigijadibalag.pdf
    • http://basumati.com/app/webroot/ckfinder/userfiles/files/vebedomukiziloxet.pdf
    • https://confidence-ist.mktechsol.com/ckfinder/userfiles/files/51019476503.pdf
    • http://ibookingkr.com/FileData/ckfinder/files/20210902_72E918C484AB96B5.pdf
    • http://xn--jt2b56wn0ap2a.com/upload/file/202109212327105565.pdf
    • http://kaus21.com/userData/board/file/54794994374.pdf
    • https://matao.ro/app/webroot/files/userfiles/files/76982670520.pdf
    • http://longarmacademy.net/fckeditor/userfiles/file/gozajobonobulitixavazi.pdf
    • http://dyneco.kr/userData/board/file/68540123490.pdf
    • https://winstar-tools.com/UserFiles/editor/file/zogimozajo.pdf
    • http://stepasidemedical.ie/images/uploads/file/72912863052.pdf
    • http://www.web-globus.de/ckfinder/userfiles/files/36964364547.pdf
    • http://dispensapertutti.com/userfiles/files/lixokumikirabosukivawino.pdf
    • http://el-system.jp/uploads/2012/files/bixetarovunifa.pdf
    • http://dunajecbiala.pl/upload/File/jabubomuwu.pdf
    • http://brukikostka.pl/uploads/page/file/nilonuxananijafa.pdf
    • http://schouteninterieurwerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1615008d975d7b---jakizetevibixopu.pdf
    • http://zentrumok.com/userfile/files/rididazifesegokomidij.pdf
    • https://associazionemusicaviva.it/uploads/file/70035249056.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b464.bin
77190cf3bfc51a8e3bb4c445f36bb4c0ed96e9181848ab136c405322c232385e		 pdf-font-stream PDF embedded font (sfnt) at offset 0xB464 10444 bytes
font_01_sfnt_off0000cc39.bin
01cd0e4798e93fb086042d610f43ddeed7bf091af48aa863f5c4a4f61b651684		 pdf-font-stream PDF embedded font (sfnt) at offset 0xCC39 16232 bytes
font_02_sfnt_off0000e212.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE212 16792 bytes
font_03_sfnt_off0000fa24.bin
7e12c280c6c4c372dde68116d788ec5cfa972227a6c62fd6475aa2740ef65c18		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFA24 18512 bytes

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