Malicious PDF — malware analysis report

Static analysis result for SHA-256 c99c85c9993348ce…

MALICIOUS

PDF

70.6 KB Created: 2021-09-27 16:32:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 27a953487e96e47a76d46263806e57bc SHA-1: eeb7743ba6d33bd8e7919c706dc5ff95d8e391d5 SHA-256: c99c85c9993348ce743e56ef0b8a0592a8b7268b7b929685a4d457262eeeffba
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript and a large number of external links. Several heuristics indicate that these links point to compromised CMS uploads and disposable hosting, suggesting a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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.
  • 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 https://archism.ru/uplcv?utm_term=crazy+speed+2+mod+apk PDF link annotation
    • http://mfplus.ba/wp-content/plugins/formcraft/file-upload/server/content/files/161480e3b9f8f4---texuzalapevup.pdfIn PDF document text
    • http://struttur-arch.it/userfiles/files/tolusesumipubumawowom.pdfIn PDF document text
    • http://unionnutritech.com/upload/files/29591955228.pdfIn PDF document text
    • http://cokhivietuc.webthoidai.com/img-vietuc/files/40920201686.pdfIn PDF document text
    • http://merrygoldholidays.com/ckfinder/userfiles/files/fuwobujiz.pdfIn PDF document text
    • https://www.revistadefiesta.com/wp-content/plugins/formcraft/file-upload/server/content/files/16143615cb0b21---xodurifabunirusot.pdfIn PDF document text
    • http://dulichtantai.com/files/uploaded/files/rokodinebojuzuke.pdfIn PDF document text
    • https://tinnituskozpont.hu/files/wutof.pdfIn PDF document text
    • https://agermag.ro/mm/file/nudivodolikame.pdfIn PDF document text
    • http://shuimotongyuan.com/userfiles/file/85896719530.pdfIn PDF document text
    • https://homestayhoian.thamtuddt.com/uploads/image/files/povorim.pdfIn PDF document text
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/161503557d9e4d---37767749250.pdfIn PDF document text
    • http://www.linkkorea.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/16134d73d36710---34067905769.pdfIn PDF document text
    • http://sayarbobinaj.com/file/25253432386.pdfIn PDF document text
    • http://kingkady.cn/uploadfile/files/sagevelet.pdfIn PDF document text
    • https://dursunguney.com/userfiles/files/levujibene.pdfIn PDF document text
    • https://jasmijnbloemengroen.nl/userfiles/file/begokiguxopo.pdfIn PDF document text
    • http://nassagroup.org/app/webroot/js/ckfinder/userfiles/files/3134991267.pdfIn PDF document text
    • http://nc-israel.ru/upload/files/21904368676.pdfIn PDF document text
    • http://uat2.hkha.com.hk/ckfinder/userfiles/files/9477636579.pdfIn PDF document text
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131425fe686d---34651980998.pdfIn PDF document text
    • https://aparcaderoshaddaichile.cl/uploads/images/files/sovozufelinekujipileligim.pdfIn PDF document text
    • http://ever-pioneer.com/upload/files/43012969972.pdfIn PDF document text
    • http://goldstecq.com/userfiles/file/pivaxininedinuzaka.pdfIn PDF document text
    • https://www.medipratik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614147e72e406---lalunufoxepejumalox.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_off0000b1e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1E9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ca00.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA00 10628 bytes
SHA-256: 2b24895f3e68c345eea896d015d9d4330afad1c0cc977cb120fb445df82489f8
font_02_sfnt_off0000e277.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE277 16648 bytes
SHA-256: fcbf73f73fc95e0dd7bc7e887746f96e8c4c7c29e2e4022467099970acd0f4d5

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