Malicious PDF — malware analysis report

Static analysis result for SHA-256 88d5666b833bc32c…

MALICIOUS

PDF

98.8 KB Created: 2021-06-26 22:27:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b12a33974267c8b40390fda549a2cf06 SHA-1: 17e87f206d2908f45d2e16d0272eadf629b4cf60 SHA-256: 88d5666b833bc32cdf22d0ef2c53f0ccdb10c750d3cf721030a49f4bb2a8c0dc
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous URLs pointing to compromised WordPress sites and disposable domains, suggesting a phishing or malware distribution scheme. The presence of external URIs and link farms on potentially compromised infrastructure strongly supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9928

Heuristics 6

  • 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
  • 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://nomylo.ru/uplcv?utm_term=use+of+parentheses+in+writing
    • http://alfavs.eu/userfiles/file/dizuriwetisonik.pdf
    • http://dagmare.de/userfiles/file/92036038588.pdf
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607ff3d363c53---wedemutenufepisa.pdf
    • http://www.nowsingapore.co.id/wp-content/plugins/formcraft/file-upload/server/content/files/1606c93ce77e2c---biloxumofadimupaxubedu.pdf
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/9eftthde56eu97lfd0igah53k1/44210238236.pdf
    • http://khiconghoixuancong.com/Khicong/admin/userfiles/file/56659563571.pdf
    • http://sakirnoopo.ru/wp-content/plugins/super-forms/uploads/php/files/a4d2e3b56b6887aaa74a8746cc4e3c7b/wigudatadofupoto.pdf
    • https://master.plus/wp-content/plugins/super-forms/uploads/php/files/59bb2ae20e247aaae1a0a25169eab0b1/gexuwopejapebinudo.pdf
    • http://azizolace.cz/images/file/32269946077.pdf
    • http://bfr-bialapodlaska.pl/userfiles/file/25985221514.pdf
    • https://yellowstonewildlife.com/53492555324.pdf
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/160a8b40f203fe---wuduzava.pdf
    • https://www.charroninc.com/wp-content/plugins/super-forms/uploads/php/files/d242f5d8d7c936e2d7eff93d5a1ebb20/56817617531.pdf
    • http://mytmbc.org/fckimage/file/31663211786.pdf
    • https://qualitylightsolutions.com/wp-content/plugins/super-forms/uploads/php/files/44bcf49abf4a96c899c2f1e2b48c0f1c/94101772227.pdf
    • http://www.naturapreserved.com/wp-content/plugins/formcraft/file-upload/server/content/files/160714ef0438d5---11834492055.pdf
    • http://stroynerud-sm.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160740fd046fba---xuwazafukobefoxosunuzaras.pdf
    • http://www.skupp.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16079e4d1b4e83---24851854370.pdf
    • https://cristiandellavedova.com/wp-content/plugins/super-forms/uploads/php/files/da2rt3dqhdej5tmoegfv128510/jotafivedodosu.pdf
    • https://www.kbstephens.com/wp-content/plugins/super-forms/uploads/php/files/b840bb3ff6dd6cd606d96f756207a1eb/24187741842.pdf
    • http://work4shop.cz/userfiles/file/wojavo.pdf
    • https://staffxrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/fef7532c943c3fc8d30a7b9ad7a1be34/27262146715.pdf
    • http://aldara-latinoamerica.com/userfiles/file/31887513766.pdf
    • https://htchninc.com/d/files/25319474970.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_off00011c34.bin
d84666c0da425ef327d5defbc775011021472b244c8931f47067fdab7e0466b4
pdf-font-stream PDF embedded font (sfnt) at offset 0x11C34 18044 bytes
font_01_sfnt_off00014bca.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x14BCA 16792 bytes
font_02_sfnt_off000163e1.bin
3f6eb063749c0115322d77aecf0f418d57c0a8d68d8e70957680b621228474f1
pdf-font-stream PDF embedded font (sfnt) at offset 0x163E1 10684 bytes