Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1a9136d21931b44…

MALICIOUS

PDF

86.5 KB Created: 2021-06-27 01:14:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 00cacb75f12d52501410672110cf86bc SHA-1: 5a65f1d37d203a26a10337ea35a12feb92bd7375 SHA-256: b1a9136d21931b440df81a0e4715b116409117a99a499e4362d5901bf8ddf2a2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics indicate the document functions as a link farm, directing users to numerous external URLs hosted on potentially compromised or disposable domains. While no scripts were explicitly extracted, the nature of PDF link farms often involves JavaScript to facilitate redirection or exploit vulnerabilities, aligning with T1059.007. The primary attack pattern observed is the use of a link farm to distribute malicious content or conduct phishing, consistent with T1566.001.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9930

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://nikken-engineer.jp/export/sd205/www/jp/r/e/gmoserver/8/6/sd0748886/nikken-engineer.jp/fckeditor/upload/file/bexone.pdf
    • https://argumentua.com/i/file/7531975206.pdf
    • https://ceadersvalet.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079253f8c053---wasur.pdf
    • https://braviengenharia.com.br/wp-content/plugins/super-forms/uploads/php/files/j77gg57lf99i2jsaeupnn4cp6r/61725716142.pdf
    • http://weifong.tw/fckimages/file/vixugalepelo.pdf
    • http://universalestetic.com/userfiles/file/488307966.pdf
    • https://aashianarealty.com/file/kukevetebitebojet.pdf
    • http://opalsolar.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160874af361c5e---jinujuxodokakipalepa.pdf
    • http://vdadanang.vn/app/webroot/assets/files/mepazawuxuzu.pdf
    • https://baptistfriends.org/media/56571932035.pdf
    • https://www.kiakaha.gr/wp-content/plugins/super-forms/uploads/php/files/3pr46viavpn1hbhbtopjetn6mn/tukemidolenevewubokaga.pdf
    • https://law.myvzl.com/wp-content/plugins/super-forms/uploads/php/files/fdb65k99jgjf4l86nge9vkn2a7/musurivulatefezefemejedu.pdf
    • https://dgaspcsm.ro/ckfinder/userfiles/files/jadajugalenodomosu.pdf
    • https://travels-ukraine.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bf59a0bdd8a---bibub.pdf
    • http://muslimofwestbengal.com/mwb/editor_upload/files/jelavewadaxuzemumuwug.pdf
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/160892aeb2cf5e---zenujoxikutavupazi.pdf
    • https://www.hinogas.com/wp-content/plugins/super-forms/uploads/php/files/hsmvkh76dcelvvc76mc05sefvm/wutotojixul.pdf
    • https://ubranni.com/uploader/files/28483105049.pdf
    • http://www.kreasoft.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1606d683080755---39399535251.pdf
    • http://bazatalty.pl/wp-content/plugins/super-forms/uploads/php/files/1cc514d9188eccc3cde488558e815c4c/guxidiwuxoxutotinamiweme.pdf
    • https://www.actionconstructionjax.com/wp-content/plugins/super-forms/uploads/php/files/a3b2f48adbc947929aed1290e19151ab/wuzivozuv.pdf
    • http://stark-tools.ru/images/uploaded/38614717105.pdf
    • http://studioingegneramato.com/userfiles/files/58196620596.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=off+the+cuff+meaning+in+english
    • 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
stream_003_off0000fc3b.bin
1621e1bf853829bdac790a09fadc70d167f6dc5f62574533ba15d71f8f7a40db
decompressed-pdf-stream PDF FlateDecoded stream at offset 0xFC3B 18572 bytes
font_00_sfnt_off0000cd17.bin
23eab5be7d39d194f9b5756657ad864eaf9634eb6662c7957e281b8739e374ed
pdf-font-stream PDF embedded font (sfnt) at offset 0xCD17 17904 bytes
font_02_sfnt_off000119f6.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x119F6 16792 bytes
font_03_sfnt_off0001320d.bin
e01c6621d443e678770c72d5d96f7df13b8d1aa116900cbc4d99a477e7708749
pdf-font-stream PDF embedded font (sfnt) at offset 0x1320D 10688 bytes