Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4c673de1a27f384…

MALICIOUS

PDF

76.1 KB Created: 2021-09-02 21:06:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e5cfc8a15b546eda503cfb8816f9bc0b SHA-1: de0ea962c4abfe1bda936c4e763ce6bf13290f93 SHA-256: a4c673de1a27f384fd6b469bc1e167714e1777f28c4e15672c7a52f967d83d63
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 external PDF files hosted on various domains. Several heuristics indicate this PDF is a link farm, with some links pointing to compromised CMS upload storage. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution through these external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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
  • 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://novichiha.ru/pic/file/23378676476.pdf
    • http://sadiqandsons.com/userfiles/files/xunefazuni.pdf
    • https://garnizone.com/userfiles/file/wozewovupavok.pdf
    • http://jikaramen.com/uploads/files/wagunomigepovul.pdf
    • https://thailonghoang.vn/upload/files/fogurujelikiwexe.pdf
    • https://www.cedicar.com/wp-content/plugins/formcraft/file-upload/server/content/files/161008a12118d1---47395911164.pdf
    • http://humanitool.ru/userfiles/file/vabetezopidi.pdf
    • http://bizwd.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b62205f3048---49889934804.pdf
    • https://duocvinhkim.com/userfiles/file/32789436882.pdf
    • http://labotinnghia.com/img/files/panerosuxujemamegigura.pdf
    • https://youstore21.com/wp-content/plugins/super-forms/uploads/php/files/3402679ac395415f5d24345deb8875bb/zidafoti.pdf
    • http://bortran.com/upload/image/file/20210626094743.pdf
    • http://pro-group.ru/userfiles/files/fadazifejekogebusipates.pdf
    • https://erdenetpost.mn/userfiles/files/bujakejajowokama.pdf
    • https://turdv.ru/SITE/files/editor/file/6081497106.pdf
    • http://staceyasp.com/UserFiles/file/9931379593.pdf
    • http://jl-vacuum.com/upload/files/10290367524.pdf
    • http://frederickfollows.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160c131706a52e---tilarurovutumenitopomilu.pdf
    • http://inteko-tula.ru/f/file/75670087819.pdf
    • https://completecollegestrategies.com/wp-content/plugins/super-forms/uploads/php/files/6f0070c6534c4de29f16f5ee32979cc6/76487546678.pdf
    • https://mt-creativestudio.com/ckfinder/userfiles/files/sibalejow.pdf
    • https://bluetact.com/ckfinder/userfiles/files/vepafazozafuxagifuxex.pdf
    • https://sv-fin.ru/wp-content/plugins/super-forms/uploads/php/files/a99631e32a05233e1cf88fb846178e8a/49730194160.pdf
    • http://didula.ru/img/file/4324685729.pdf
    • http://petukmahaaaraj.com/userfiles/file/53053734219.pdf
    • http://cn-polylysine.com/d/files/bafozajazitimivobageteko.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=employee+termination+letter+sample+pdf+uk
    • 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_off0000c767.bin
b330d1f9d1e03245cdbaf255cd55c5e3bcf2032bbc9a5763e65a97c1217311f6
pdf-font-stream PDF embedded font (sfnt) at offset 0xC767 16404 bytes
font_01_sfnt_off0000f13a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF13A 16792 bytes
font_02_sfnt_off00010951.bin
dad9dc282a75fff1254b95b6256b09367a321068bebd05f370de9cb9b4c9539f
pdf-font-stream PDF embedded font (sfnt) at offset 0x10951 10948 bytes