Malicious PDF — malware analysis report

Static analysis result for SHA-256 91a40e293e851cff…

MALICIOUS

PDF

72.4 KB Created: 2021-10-02 15:46:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: aa9ac675646f12aaf5d27f3dc81a2292 SHA-1: 4fa1be9c784da7bf31822e51149cc4a2b48e70b0 SHA-256: 91a40e293e851cfffc42e5ecf7c0fef5b0353931791746e5ee77f1ab316bb64e
164 Risk Score

Malware Insights

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

The sample contains embedded JavaScript, which is often used to execute malicious code or redirect users. The PDF also functions as a link farm, pointing to numerous URLs hosted on compromised or disposable domains, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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 http://stagelight.pl/userfiles/files/58345910021.pdf In PDF document text
    • https://birudongker.com/contents/files/rapojivudarasekajaku.pdfIn PDF document text
    • http://alemotta.com/resources/original/file/nitiximutekekuroxubudirom.pdfIn PDF document text
    • https://www.isgs.org/wp-content/plugins/super-forms/uploads/php/files/9b43bd2cb4d6ea6dd767f8e390c93ac3/wadebarimonulomog.pdfIn PDF document text
    • http://kovacsoltvaskerites.hu/images/file/24896359925.pdfIn PDF document text
    • https://www.emmabowman.com/wp-content/plugins/super-forms/uploads/php/files/f115cce3610fcd30b9c64ac89a1ad2f1/98435806796.pdfIn PDF document text
    • http://rosritual.su/app/webroot/js/ckfinder/userfiles/files/konelevimevowenax.pdfIn PDF document text
    • http://becro-plast.hr/wp-content/plugins/formcraft/file-upload/server/content/files/1613f97cdf3239---55306463051.pdfIn PDF document text
    • https://avela.md/userfiles/file/30437980654.pdfIn PDF document text
    • https://aiwcecckolkata.org/FCKeditor/file/20714119503.pdfIn PDF document text
    • https://contact-house.com/fckeditor/upload/file/64862714994.pdfIn PDF document text
    • http://stapper.de/sites/default/files/userfilesfile/76430024921.pdfIn PDF document text
    • https://gotoko.com/cmsv2/upload/files/97847220593.pdfIn PDF document text
    • http://tplustech.com/images/ckeditor/files/pubilosugakelegutiz.pdfIn PDF document text
    • https://sikahaiphong.com/images/news/files/66429417750.pdfIn PDF document text
    • http://opusincertum.it/userfiles/files/fivugaxiwizasomabujefusu.pdfIn PDF document text
    • https://www.modianodesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614c4732cd616---31285570177.pdfIn PDF document text
    • http://ranfeng.com/userfiles/file/2021-9///2021929844154583.pdfIn PDF document text
    • http://sasolution.kr/userfiles/file/57801167834.pdfIn PDF document text
    • http://maezawa-jidousha.com/js/upload/files/44874670904.pdfIn PDF document text
    • http://www.radiopopiatej.com/wp-content/plugins/formcraft/file-upload/server/content/files/16152a815afdd7---worapuxovivodiv.pdfIn PDF document text
    • http://etre-belle.su/images/file/69204189386.pdfIn PDF document text
    • https://conexus-study-abroad-travel.com/ckfinder/userfiles/file/4387058351.pdfIn PDF document text
    • http://redigonda.it/userfiles/files/32860294400.pdfIn PDF document text
    • http://savalis.ru/userfiles/file/muwugujukojurukapurixo.pdfIn PDF document text
    • https://imihwa.com/uploads/image/20210920/files/20210920015235.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=starcraft+2+for+beginnersPDF 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_off0000b568.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB568 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cd7a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD7A 17796 bytes
SHA-256: 3d5c886705d39b625b2dd1f2772954fe2ee20985cbb4da0cce031248c2f06981
font_02_sfnt_off0000faff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAFF 10800 bytes
SHA-256: 973d9278877086802417754ce9508b36a3b25c0f0cc9651f963dd904058357ed

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