Malicious PDF — malware analysis report

Static analysis result for SHA-256 538aced0a75454c8…

MALICIOUS

PDF

74.1 KB Created: 2021-09-18 17:49:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 683e254dff56c78ff0c1dcf92124485c SHA-1: ca224d1aa6764b3aced863fd79991b7bdd01afb1 SHA-256: 538aced0a75454c89ecce53f272fa309c0fd841fe77d81ba5f37a0dda9dc3533
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by ML classifiers and ClamAV as malicious, with specific heuristics indicating it functions as a link farm and a lure for recovery secrets or private keys. The presence of numerous external URIs, many pointing to potentially disposable domains, supports the conclusion that this document is designed to redirect users to malicious content, likely for phishing or malware distribution. No scripts were extracted, but the overall structure and heuristics point to a social engineering attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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
  • Recovery secret / private key request critical SE_SECRET_RECOVERY_LURE
    Document requests recovery phrases, private keys, backup codes, or saved passwords. Requests for these secrets in a document are high-risk.
  • 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://smolninskayahotel.com/userfiles/file/29534851085.pdf In PDF document text
    • http://graphicyazd.com/ckfinder/userfiles/files/nipofosowagonenokutolimu.pdfIn PDF document text
    • https://drlalashow.com/php/billboard/uploads/file/rugevizi.pdfIn PDF document text
    • http://bunny888.com/ckfinder/userfiles/files/logadejifudesoselinojeref.pdfIn PDF document text
    • http://movesearchesuk.com/userfiles/file/rogagopowajulemowavej.pdfIn PDF document text
    • http://southerncross-ex.com/images/blog/file/ridofaxa.pdfIn PDF document text
    • https://k-newsletter.com/ckupload/files/gogepekosebetuvo.pdfIn PDF document text
    • http://sweethomedelivery.com/ckeditor/ckfinder/core/connector/php/uploads/files/99263258554.pdfIn PDF document text
    • http://intersonik.eu/upload/files/6969886013.pdfIn PDF document text
    • https://maggievanostrand.com/uploads/media/file/82261455815.pdfIn PDF document text
    • https://cubic.is/userfiles/file/51864783524.pdfIn PDF document text
    • http://meadescafe.com/userfiles/file/65029753089.pdfIn PDF document text
    • https://www.kuwaitpolyurethane.com/ckfinder/userfiles/files/12965645875.pdfIn PDF document text
    • http://www.iso-clean.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1613ed4dd8b2f3---90437483071.pdfIn PDF document text
    • https://er-cardiff.com/eurostyl/photos/file/89728346948.pdfIn PDF document text
    • http://sasnowosielski.com/ckfinder/userfiles/files/77569036755.pdfIn PDF document text
    • https://kheops-so.fr/ckfinder/userfiles/files/71949006206.pdfIn PDF document text
    • http://essentielles-theater.de/UserFiles/File/85401820041.pdfIn PDF document text
    • http://bettaletroom.com/file_media/file_image/file/marina.pdfIn PDF document text
    • http://marcus-1.com/FileData/ckfinder/files/20210903_F6A8CC8808BF06F2.pdfIn PDF document text
    • https://giant-nano.com/app/webroot/userfiles/files/nalive.pdfIn PDF document text
    • https://goodline.by/userfiles/file/43308871446.pdfIn PDF document text
    • http://vsrru.ru/userfiles/file/42807110229.pdfIn PDF document text
    • http://bjzjygj.com/fckeditor/editor/filemanager/connectors/php/userfiles/file/39064076507.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=android+marketplace+downloadPDF link annotation
    • 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_off0000c140.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC140 16160 bytes
SHA-256: f0f16e38e806fa47df5e4e6ef03a8f57ac6d9281878824121143015b7f33c1b0
font_01_sfnt_off0000ead4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAD4 10664 bytes
SHA-256: eb35001cf0d939712427f6129ca2a9047b742cd1267d1de3725c4d4c1080e556
font_02_sfnt_off00010342.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10342 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1