Malicious PDF — malware analysis report

Static analysis result for SHA-256 23f5eab3f603556c…

MALICIOUS

PDF

69.3 KB Created: 2021-09-27 06:46:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: efe896276871f7d2274ac0b17a6e0c98 SHA-1: 4b5a2305023d84599f41edd3e2441316463b9168 SHA-256: 23f5eab3f603556ce421cb5eb783b1a9f1243ec85836198b262d41ce82aaed51
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs hosted on potentially compromised or disposable domains. The document body is heavily obfuscated and unreadable, suggesting it's not intended for direct user interaction but rather to facilitate the redirection to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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 http://aliguoriarchitetto.eu/userfiles/files/jebedufudaxinedubezeror.pdf In PDF document text
    • https://mariapolis.net/ckfinder/userfiles/files/bofibaxozuvosufiviwi.pdfIn PDF document text
    • https://fortworthdental.net/cmsCart/upload/file/xaxeg.pdfIn PDF document text
    • https://activepymes.com/pub/file/5345227333.pdfIn PDF document text
    • http://toflight.mobi/attachment/ckeditor/files/9d6d3a6a674aabc6b227b0873c47d7ee.pdfIn PDF document text
    • https://www.ediliziaindustriale.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613bc91e08c93---43817390811.pdfIn PDF document text
    • https://webmodeli.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614c8f58d7384---71619639398.pdfIn PDF document text
    • http://podhoru.cz/userfiles/file/devad.pdfIn PDF document text
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/dbvln9rg78hkscebf86ls5m9ba/tijazijasipozemewodal.pdfIn PDF document text
    • http://zl369.net/userfiles/file/10352288970.pdfIn PDF document text
    • http://www.chiringuitomediterraneo.com/ckfinder/userfiles/files/40719111422.pdfIn PDF document text
    • https://ip-kamera-rendszer.nuttydog.hu/ckfinder/userfiles/files/73747497553.pdfIn PDF document text
    • http://bndweb.nl/upload/files/rurojizazuxip.pdfIn PDF document text
    • http://poltinik.ru/userfiles/file/70608466794.pdfIn PDF document text
    • http://dui-antidote.com/images/userfiles/file/padevelofuwenapemejapitu.pdfIn PDF document text
    • https://cengilli.com/icerik_images/file/noludufa.pdfIn PDF document text
    • https://www.dekleinewerf.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16130c4104a4a9---78600624400.pdfIn PDF document text
    • http://k9careclinic.in/ckeditor/ckfinder/userfiles/files/82842729353.pdfIn PDF document text
    • https://ap-qatar.com/userfiles/files/19803758712.pdfIn PDF document text
    • http://cortocircuito.trialpanel.com/images/Upload/files/basonekikutoni.pdfIn PDF document text
    • http://debandhelder.nl/ckfinder/userfiles/files/kugatamu.pdfIn PDF document text
    • https://xulynuocphangiathinh.vn/images/pic/file/wapep.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=how+can+i+show+a+secret+conversation+on+messenger+on+pcPDF 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_off0000b036.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB036 10920 bytes
SHA-256: f291c03a80ee9c7afc0423edb5d72a2fb175ed479b5d9b8c42bb66838d11d4b3
font_01_sfnt_off0000c95e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC95E 14952 bytes
SHA-256: 835a3d67c059d34a52323a2f9e3a53020f19b16baa32abaee16cd88496adbc27
font_02_sfnt_off0000eeec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEEC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1