Malicious PDF — malware analysis report

Static analysis result for SHA-256 e21573d38955e08b…

MALICIOUS

PDF

70.7 KB Created: 2021-09-30 21:04:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 5031dd712fa998dc3256ee21023428eb SHA-1: da897a111a467a3accede4c46f666f8bf7405a5d SHA-256: e21573d38955e08be55e5428632c95d6b8aff4142eee21b1c20b3f6baa66bbad
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs, many of which point to compromised or disposable hosting domains, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. The presence of multiple links on potentially compromised sites like stkvn.ru further supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 http://bowlingkillers.com/imgdb/files/4230514389.pdf
    • http://grapes4u.ca/sites/all/sites/grapes4u.ca/files/40082370313.pdf
    • http://asia-test.informacittadino.net/media/files/41628418424.pdf
    • http://sghscsjamarai.org/guruhargobind/userfiles/file/buratinobutelel.pdf
    • http://unionnutritech.com/upload/files/98417505386.pdf
    • http://www.medicellbank.com/userfiles/files/69570214258.pdf
    • http://www.enfersalus.com/ckfinder/userfiles/files/kinexo.pdf
    • http://ontis.sk/editor_uploads/system/files/59037755195.pdf
    • http://www.corazondelsol.es/ckfinder/userfiles/files/45193079874.pdf
    • http://stkvn.ru/wp-content/plugins/super-forms/uploads/php/files/671a46a3bdb8425d5adcfd4bb1d2588a/22178284769.pdf
    • http://houselandia.ru/files/fefakuzox.pdf
    • https://humantouchtranslations.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/1615567ed34414---rubelitir.pdf
    • http://signexpowholesale.com/project-new/christianbook/upload_images/file/banesanovafizorojuvewu.pdf
    • http://safeabortionnepal.com/userfiles/file/fozunuwuke.pdf
    • https://htapigroup3.com/contents/files/mibunubevelu.pdf
    • http://fitsiluet.cz/data/file/gazigerevedafesipineguv.pdf
    • http://constantemails.com/userfiles/file/1631299602gubevusafuta.pdf
    • http://cdseoulps.com/uploadfile/fckeditor/file/tixisoxufodu.pdf
    • http://szyuangang.com/UserFiles/file///80978636280.pdf
    • https://kuechentreff-schmid.de/wp-content/plugins/super-forms/uploads/php/files/b8ouuskko5bpi6ocavc8b9c51p/63137645740.pdf
    • http://cuboni.com/uploadfile/hong202109160046396723.pdf
    • http://epmachine.ru/d/files/xopenivedopuvokuxexefede.pdf
    • http://gdgom.com/upload/file/210908135611348530dmy9a9b6r3ni.pdf
    • http://sewakendragroup.com/userfiles/file/29609000832.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=extension+for+android+software+files+crossword
    • 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_off0000b2cd.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xB2CD 16792 bytes
font_01_sfnt_off0000cae4.bin
d51676becd7bbc843cbbf82fb236c2865747a02b8199078a6ef8df52cfdcecec
pdf-font-stream PDF embedded font (sfnt) at offset 0xCAE4 10640 bytes
font_02_sfnt_off0000e375.bin
ae7b7d0a772f7ab735c6b408445bc698e67a1401989fc27fd7e7a81e6fbba71b
pdf-font-stream PDF embedded font (sfnt) at offset 0xE375 15608 bytes