Malicious PDF — malware analysis report

Static analysis result for SHA-256 acd8c55350221216…

MALICIOUS

PDF

71.4 KB Created: 2021-09-18 03:30:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 4bd909de7c168bcca94d211aaec8933c SHA-1: b4dc95a339c5d96dd8776a5c0b076d49a8806227 SHA-256: acd8c55350221216995847b5c2c51360561a7ab0526014c0336b9ee7b180b4f4
164 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ClamAV as a phishing trojan and by an ML classifier. It contains embedded JavaScript and numerous external URIs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users to malicious content. The presence of embedded JavaScript suggests an attempt to execute malicious code within the PDF viewer.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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 http://skkl.cn/filespath/files/20210902055546.pdf In PDF document text
    • http://k3projekt.pl/uploads/userfiles/files/bovozepekunafivikibapi.pdfIn PDF document text
    • http://cybernet.asia/UserFiles/File/81432123688.pdfIn PDF document text
    • http://lexus-custom.com/js/upload/files/nuxalariteveperug.pdfIn PDF document text
    • https://atavio.ru/files/file/xomukamol.pdfIn PDF document text
    • https://vietnaminsight.biz/ckfinder/userfiles/files/ramujufujusom.pdfIn PDF document text
    • https://semangkabiji.com/contents/files/55292661829.pdfIn PDF document text
    • https://anandamsanyal.com/userfiles/file/53518683410.pdfIn PDF document text
    • https://aromamarketing.md/img/files/75897224362.pdfIn PDF document text
    • https://dynasty888.com/image/files/20210917_172313.pdfIn PDF document text
    • http://inewbus.com/wp-content/plugins/super-forms/uploads/php/files/g0l076q9vgm4nik6qnc5m9u291/jitanoreparaxupis.pdfIn PDF document text
    • https://soportedevida.mx/ckfinder/userfiles/files/pibobek.pdfIn PDF document text
    • http://zezoalza.com/ckupload/files/timolesujosivofupavure.pdfIn PDF document text
    • https://redac.ch/upload/pebapewujaruwefiwibuzimo.pdfIn PDF document text
    • http://ancheng-medical.com/uploadfile/files/15683048869.pdfIn PDF document text
    • http://emeat.ru/var/files/bivigegodogagadi.pdfIn PDF document text
    • https://jss-moms.si/upload/File/rinuwifusuvugabipumezo.pdfIn PDF document text
    • http://caerulumpharma.com/upload/files/3677523648.pdfIn PDF document text
    • http://intechsol.kz/wp-content/plugins/formcraft/file-upload/server/content/files/16131ad1add4c9---nimonipewolasu.pdfIn PDF document text
    • http://mgrima.com/files/file/15129866780.pdfIn PDF document text
    • https://web-sila.ru/wp-content/plugins/super-forms/uploads/php/files/0e1c0d3311385f3db866449ddafe9863/62991277202.pdfIn PDF document text
    • http://objetivovender.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613bbb00e6844---maxomafopemikizi.pdfIn PDF document text
    • https://unitedfightalliance.com/ckfinder/userfiles/files/jawidelunafatuneripore.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=view+saved+wifi+password+on+androidPDF link annotation
    • 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_off0000b52d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB52D 10468 bytes
SHA-256: f40c1e18d642c4d81035c60599a3eb56c28d1bb4a7404223e7622913ba4ba32a
font_01_sfnt_off0000cd20.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD20 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e532.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE532 16524 bytes
SHA-256: 930afe39b4c04121ab3f39e1c6cf8230c0f38c93cbfec639746946f80afe0e36

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