Malicious PDF — malware analysis report

Static analysis result for SHA-256 6733cb39db8e01a0…

MALICIOUS

PDF

80.2 KB Created: 2021-09-17 13:28:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 42a42a05e1fae56572084795f6fe7978 SHA-1: 8060fd4364b0da15c820745100e8349f4a6e7d66 SHA-256: 6733cb39db8e01a0e129b60ac06d37da256cdd4808b5c17b1b88b5d1f7f66f24
164 Risk Score

Malware Insights

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

The PDF contains numerous external links, many of which point to other PDF files hosted on potentially compromised or disposable domains, suggesting a link farm designed to distribute malware. The presence of a 'download button' heuristic and ClamAV detection as 'Pdf.Phishing.Trojan' further supports its malicious nature. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://catamma.ru/uplcv?utm_term=a+to+z+mysteries+books+free+download
    • http://rgn2u.com/userfiles/files/fejipusezaxenufeboxoneles.pdf
    • http://dxline.eu/userfiles/file/13066318422.pdf
    • https://izometal.net/mm/file/1612552424.pdf
    • http://msci.com.ng/wp-content/plugins/formcraft/file-upload/server/content/files/16140bd14690fa---61541419959.pdf
    • https://angkoronetour.com/userfiles/file/xufipuwubulo.pdf
    • https://dusunceokulu.net/resimler/files/80285954975.pdf
    • https://slide-bearing.com/d/files/bizukijopefikereje.pdf
    • http://al-bandak.com/userfiles/file/zikinopus.pdf
    • https://almondzwealth.com/administrator/imagetemp/file/voneribarowejamirakala.pdf
    • https://citytrafik.nu/images/file/4543836895.pdf
    • https://www.stnedu.com/ckfinder/upload/files/9418201095.pdf
    • http://e-menu.hu/editor_up/85794582221.pdf
    • https://www.financedeclined.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613e1ccbc3c12---sonezise.pdf
    • https://stewsites.com/wp-content/plugins/super-forms/uploads/php/files/ad7f4dfaecfb93f698ca1f0e42ec2b8f/xebasovizuzakujefeke.pdf
    • https://www.18fire.com/wp-content/plugins/super-forms/uploads/php/files/c5b96ef58ed912df2fbecf177e90dc61/lamamoniradazeka.pdf
    • http://thainightjob.com/ckfinder/userfiles/files/24502278398.pdf
    • https://web-sila.ru/wp-content/plugins/super-forms/uploads/php/files/0cef71568da562ba6e1dd4be3a5fa78c/17653249049.pdf
    • http://osteriailgalloelinnamorata.com/userfiles/files/6133514048.pdf
    • http://shmgec.com/Uploadfiles/files/60583049993.pdf
    • http://bocghebinhduong.com/media/ftp/file/38024144340.pdf
    • http://www.barbazan-debat.fr/ckfinder/userfiles/files/3704907131.pdf
    • http://inphuduong.vn/upload/files/80546530693.pdf
    • http://pastadimatteo.com/ckfinder/userfiles/files/juguniwenebarukuj.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_off0000d1cb.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xD1CB 16792 bytes
font_01_sfnt_off0000e9dd.bin
b1ee3326c5e552117bd6f3e9de13846aeffedac2d83c641b4412bc17ab7b0d62
pdf-font-stream PDF embedded font (sfnt) at offset 0xE9DD 18600 bytes
font_02_sfnt_off00011982.bin
8deb073c305680d82edceae8fc12af4c9b0e9fc962287a7b8b7e46a323663664
pdf-font-stream PDF embedded font (sfnt) at offset 0x11982 10988 bytes