Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d7d824101ddfd1…

MALICIOUS

PDF

65.9 KB Created: 2021-09-24 18:09:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 483e60a5efc28e786d2b4305da935b37 SHA-1: 6da2625500722a95a389f547657f8682a3f754b9 SHA-256: 81d7d824101ddfd1ab214c9ab20634896fb4125877b6568e46cdd64c52f8018d
154 Risk Score

Malware Insights

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

The PDF document contains a link farm pointing to numerous external URLs, with several hosted on compromised CMS upload storage. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. No scripts were extracted, but the structure and URL analysis are sufficient to assess the threat.

Machine Learning

  • Nyx PDF Classifier malicious score 0.5448

Heuristics 5

  • 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
  • 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://www.nstoplana.rs/ckfinder/userfiles/files/39264787021.pdf In PDF document text
    • https://profm.hu/files/file/35748712759.pdfIn PDF document text
    • http://secretinvitation.net/images/files/29800141399.pdfIn PDF document text
    • http://www.scenekunstskolen-efteruddannelsen.dk/ckfinder/userfiles/files/21625489488.pdfIn PDF document text
    • http://langmypham.com/luutru/files/pefipejuvolazi.pdfIn PDF document text
    • https://www.oalysa.cz/ckfinder/userfiles/files/19860826634.pdfIn PDF document text
    • http://murasakijr.com/uploads/files/kiguguzetopugatakulodav.pdfIn PDF document text
    • http://thestarbusan.net/FileData/ckfinder/files/20210921_E243D37B708656B9.pdfIn PDF document text
    • https://lerong.vn/wp-content/plugins/super-forms/uploads/php/files/55ea99b7e9bac8e06fcc1407d6e0289a/59283492813.pdfIn PDF document text
    • https://www.adoz.cz/ckfinder/userfiles/files/besokibomugupasa.pdfIn PDF document text
    • http://bygreenpure.com/userfiles/file/kepolul.pdfIn PDF document text
    • https://promptcorporate.com/ckeditor/ckfinder/userfiles/files/16928596450.pdfIn PDF document text
    • https://detectiveoffice.net/userfiles/file/99073811071.pdfIn PDF document text
    • http://fosterfreezesantarosa.com/uploads/files/17267032229.pdfIn PDF document text
    • http://xn--j1aii.su/userfiles/file/sikariweboxi.pdfIn PDF document text
    • http://gradn.ru/uploades/fckeditorfile/kejupejok.pdfIn PDF document text
    • http://jnejendomsdrift.dk/userfiles/file/jalinel.pdfIn PDF document text
    • https://olamare.com/img/uploaded/file/17297666219.pdfIn PDF document text
    • http://www.shipsupply.co.mz/wp-content/plugins/formcraft/file-upload/server/content/files/1613b8bdc6511f---suvesositararurufafujuku.pdfIn PDF document text
    • https://roshnaai.com/ckfinder/userfiles/files/59331706939.pdfIn PDF document text
    • http://www.ebsjosepirosamaria.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132d389eb264---43865755243.pdfIn PDF document text
    • https://kebecelectrique.com/upload/editor/file/81403577529.pdfIn PDF document text
    • http://cn-daomeng.com/upload/userfiles/files/7dabaa598739d856d938d9072dab4414.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=how+to+make+violet+colour+by+mixing+two+coloursPDF link annotation
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b49b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB49B 17208 bytes
SHA-256: 8a8c044b90e5823a03fbd8f4e576b19f68647afd0cb55b321cf824ac03c26bcc
font_01_sfnt_off0000e0e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0E4 11264 bytes
SHA-256: 29132d01323a32e11900c01110a9b33a4d2bba5ce228f13083b004059ea7e205

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