Malicious PDF — malware analysis report

Static analysis result for SHA-256 9725f2a751fa4540…

MALICIOUS

PDF

73.0 KB Created: 2021-09-14 22:18:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: a045d3b2981cf45b07697ca48dd8c101 SHA-1: 6120bd3dbef8ccaed7c61d4247805e2ef2452217 SHA-256: 9725f2a751fa4540b4978331e9eacf508e83fa21fcc277bb32795cc945fe84e9
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, some hosted on compromised WordPress sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9940

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 https://chcial.ru/uplcv?utm_term=android+studio+transition+between+activities
    • https://monarchwinemerchants.com/wp-content/plugins/super-forms/uploads/php/files/8b1516a0a875c8f959c42cf3572f090e/kijivaviboku.pdf
    • https://hometutorsdelhi.com/userfiles/files/lakibozegizovim.pdf
    • http://swiss-ex.com/images/blog/file/janegarunevip.pdf
    • https://www.mftelhas.com.br/adm/Editor/ckfinder/userfiles/files/kuwamajatabukupif.pdf
    • http://sity-luxe.ru/userfiles/file/jepageg.pdf
    • http://sys-svinding.dk/userfiles/file/15919828294.pdf
    • https://fairtradeportal.pl/userfiles/file/43126573731.pdf
    • https://sevsport.info/wp-content/plugins/super-forms/uploads/php/files/8cac227e90f29438067c95fd442e4567/tagixugorov.pdf
    • https://altstudio.be/app/webroot/uploads/file/81295659615.pdf
    • http://fandimnarodaku.cz/upload/file/jixupafetidapakalusakog.pdf
    • http://kleinschadenexpert.com/userfiles/file/55902686370.pdf
    • https://barrier.exma.cl/ckfinder/userfiles/files/talariwelega.pdf
    • http://autoklej.pl/app/webroot/media/files/74680835602.pdf
    • http://acecaalcoy.com/userfiles/file/6607107655.pdf
    • https://4of100churchstreet.com/assets/media/files/fubarowixoluxurafogopa.pdf
    • http://nataliashishkina.com/userfiles/file/41848837566.pdf
    • http://allier-genealogie.org/File:/jamuzevokubupefamasi.pdf
    • http://shortguycentral.com/ck_uploads/files/48400939055.pdf
    • https://cananalimdar.com/wp-content/plugins/super-forms/uploads/php/files/r3us46qhs145kn3v4dr2kuno2h/43268365569.pdf
    • https://socialacademy.gr/wp-content/plugins/super-forms/uploads/php/files/51f75c8d54e6225bf295f61fa8e09a2d/20008140787.pdf
    • https://ambient-interier.cz/files/files/88330725597.pdf
    • https://gospel-streams.com/asset/ckfinder/userfiles/files/nezam.pdf
    • http://195exim.com/datas/files/39082172981.pdf
    • https://mimpishio.com/contents/files/895682822.pdf
    • https://jin-hung.com/userfiles/file/76688344570.pdf
    • https://hyosungulf.com/uploads/file/renagemexipuxibulopowut.pdf
    • 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_off0000bcbe.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xBCBE 16792 bytes
font_01_sfnt_off0000d4d0.bin
1d0b90599fc2f79c91394ee897585032e1a8d8ab3274fcc707d039587e3f15e0
pdf-font-stream PDF embedded font (sfnt) at offset 0xD4D0 15728 bytes
font_02_sfnt_off0000fd0c.bin
e795ecd6bc3cd9c63370b237390eaf15b9aa468ccf87541190becde459f94f1c
pdf-font-stream PDF embedded font (sfnt) at offset 0xFD0C 10688 bytes