Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4171062dd323d1a…

MALICIOUS

PDF

69.6 KB Created: 2021-09-26 03:27:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 68ba33622d04265a54248d4ef92890d1 SHA-1: 4aa1f6ea981a69bb98bf87a0353a53ef954df0e6 SHA-256: c4171062dd323d1a93bd67af8196892cdafc1847800e9b3ada536e20a11e8ded
126 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier indicating maliciousness. The presence of numerous embedded URLs, many pointing to disposable hosting and employing UTM parameters, strongly suggests a phishing or link-farming attempt. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further indicating a non-legitimate purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9909

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
  • 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://cructi.ru/uplcv?utm_term=dark+mode+chrome+search PDF link annotation
    • http://kaymccarthy.com/immagini/file/69925740182.pdfIn PDF document text
    • https://semagro-msw.ru/pics/images/file/zewobelunotosikejidena.pdfIn PDF document text
    • https://patriciobanados.cl/upload/file/In PDF document text
    • https://aglogistics-bo.net/userfiles/file/92265633245.pdfIn PDF document text
    • https://reniuved.it/file/59847503451.pdfIn PDF document text
    • https://anandalaya.in/resources/file/5590483722.pdfIn PDF document text
    • https://bisleri.genefied.co/ckfinder/userfiles/files/gadurisadibulomer.pdfIn PDF document text
    • http://xszhuhai.com/uploadfiles/files/74669952884.pdfIn PDF document text
    • http://miyagi.chi-kara.net/Upload/files/bupikafaxakuxolot.pdfIn PDF document text
    • http://libron.pl/fckupload/assets/file/jojupoxodo.pdfIn PDF document text
    • https://windsbs.biz/files/file/gasewog.pdfIn PDF document text
    • http://denda.co.kr/ckfinder/userfiles/files/gozowo.pdfIn PDF document text
    • http://planet-for-events.de/userfiles/file/36908034454.pdfIn PDF document text
    • http://www.alfapilates.pl/upload/file/24184152268.pdfIn PDF document text
    • http://originalbau.hu/imagesfiles/80647885886.pdfIn PDF document text
    • http://retrievers.su/ckfinder/userfiles/files/9953140848.pdfIn PDF document text
    • https://szabobuszrendeles.hu/files/files/kedosurixujolu.pdfIn PDF document text
    • http://daiwavn.com/uploads/image/files/sepozebedoratokotu.pdfIn PDF document text
    • http://aqua4you.hu/userfiles/file/22276875132.pdfIn PDF document text
    • http://avvocato-callegaro.it/public/file/51706514783.pdfIn PDF document text
    • http://naim.naparts.com/images/fck/file/repor.pdfIn PDF document text
    • https://tselectromechanical.com/uploads/CKfiles/files/dokawokatirajajum.pdfIn PDF document text
    • http://ipublicity.cz/data/file/42380061436.pdfIn PDF document text
    • https://rm-parketi.si/uploads/38721417745.pdfIn PDF document text
    • http://trips-in.com/ckupload/files/soribetanaserisobimip.pdfIn PDF document text
    • https://jager-ig.tw/up_photo/file/63376245777.pdfIn PDF document text
    • http://archgeo-leszno.pl/uploads/userfiles/files/25037449535.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_off0000b2f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB2F5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cb07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB07 15060 bytes
SHA-256: 082b1f51f39f81f69459b341309bf87ea6aa480c2b087c8020a27c2ae7650b54
font_02_sfnt_off0000f0e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0E1 10388 bytes
SHA-256: 75f87424aa9927f9dfac7f75953f8fe8da3476d0dde278f513c79fbecbb5ee6a