Malicious PDF — malware analysis report

Static analysis result for SHA-256 23861f88f5fb677e…

MALICIOUS

PDF

82.6 KB Created: 2021-09-08 18:09:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: d3a0487cd47d2b855ce3ce9ffb76db70 SHA-1: e773d02a62d7682a1946cbe5778ed262cf5358f5 SHA-256: 23861f88f5fb677ed6f78829a883516bee9a243b74ebe5b1d1a87a5cdc88b8ae
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to distribute traffic. The ML classifier strongly flagged this PDF as malicious. While no scripts were extracted, the presence of a link farm suggests the document is intended to lead users to malicious content or phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 5

  • 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://philabc.ru/uplcv?utm_term=instagram+template+for+students+pdf PDF link annotation
    • http://cybernet.asia/UserFiles/File/karulavawimegokesodavot.pdfIn PDF document text
    • https://mahae.hu/files/files/resen.pdfIn PDF document text
    • http://secretlove.ch/ckfinder/userfiles/files/72836447016.pdfIn PDF document text
    • http://solis.altrodesign.eu/ckfinder/userfiles/files/94368905825.pdfIn PDF document text
    • http://registermycompany.in/admin/userfiles/file/jilikolukovusurerite.pdfIn PDF document text
    • http://www.leesii.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134f0d35a21f---nalejimodo.pdfIn PDF document text
    • http://cnwt.mgo.cool/upfile/files/2021/09/03/fosanunipubi.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/16132abc505b1d---92161768068.pdfIn PDF document text
    • https://tcufroghouses.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613643623ffc4---21023540361.pdfIn PDF document text
    • http://phutungototuanphat.com/img-tvdl/files/supiv.pdfIn PDF document text
    • https://aviseco.ro/userfiles/file/36991963968.pdfIn PDF document text
    • http://myucmas.com/userfiles/file/roviwokomajis.pdfIn PDF document text
    • http://artmetinc.com/wp-content/plugins/formcraft/file-upload/server/content/files/161304bf91bc72---duduwabazobozew.pdfIn PDF document text
    • http://leaders-adv.net/userfiles/file/28384045325.pdfIn PDF document text
    • https://pui-vital.ro/msg_media/file/lewusol.pdfIn PDF document text
    • http://montesantangelo.it/files/files/91795666176.pdfIn PDF document text
    • http://megalaserasia.com/upload///17188705845.pdfIn PDF document text
    • https://emilline.dk/ckfinder/userfiles/files/89500044047.pdfIn PDF document text
    • http://opusbiz.kr/data/editor/file/60284621061338af4659c0.pdfIn PDF document text
    • https://tomorrowhubs.com/upload/users/files/fupisiva.pdfIn PDF document text
    • http://ahknchem.com/upload/files/69937487486.pdfIn PDF document text
    • http://bestpokeya.com/uploads/files/zalotekovosetexudefega.pdfIn PDF document text
    • https://livres-arts.com/ckfinder/userfiles/files/25569302920.pdfIn PDF document text
    • 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_off0000da2f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA2F 10800 bytes
SHA-256: 706984802160e4f5bbf3803b01cc965b4d31889022041bab093490731d2f3873
font_01_sfnt_off0000f2dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2DC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010aee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AEE 19276 bytes
SHA-256: 1ddd08873943f8346aefa888b6d13bab7db36e0d53df4dfabd36e61d92b330ea