Malicious PDF — malware analysis report

Static analysis result for SHA-256 81573ab400eaaab3…

MALICIOUS

PDF

78.1 KB Created: 2021-09-23 04:58:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 7c5e1c4a4dc582754e54c832af7e8bce SHA-1: dd6d9d4951b46d5559e28bcff329be04caab5cc1 SHA-256: 81573ab400eaaab3c75645e2ea6a778ec479b35bc85a4e8794ad41e2b81052a0
164 Risk Score

Malware Insights

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

The file was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier with high confidence. It contains numerous external links, some pointing to compromised CMS uploads and disposable hosting, suggesting a link farm designed to redirect users. The presence of a 'download button' heuristic further supports a lure-based attack pattern. While no scripts were explicitly extracted, the PDF structure and external links indicate it's likely designed to exploit vulnerabilities or trick users into downloading a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://pistant.ru/uplcv?utm_term=stealth+master+mod PDF link annotation
    • http://fornacedelia.it/userfiles/files/nakosube.pdfIn PDF document text
    • http://gilendor.cz/userfiles/file/boketuw.pdfIn PDF document text
    • http://maremio.ru/admin/ckfinder/userfiles/files/55103199116.pdfIn PDF document text
    • http://hanyangsteel.com/files/fckeditor/file/14659491876137eeb6044dd.pdfIn PDF document text
    • https://wecareu.net/ckfinder/userfiles/files/fepedenavu.pdfIn PDF document text
    • http://chaitraglaze.com/uploads/1819588340.pdfIn PDF document text
    • https://kasihpaham.com/contents/files/96256934574.pdfIn PDF document text
    • http://www.radio-kum.si/data/files/fivujuxaxuzebamo.pdfIn PDF document text
    • https://muratay.nl/userfiles/file/16528183962.pdfIn PDF document text
    • http://www.cenlafilm.com/siteuploads/editorimg/file/zifapamafajumaxezaj.pdfIn PDF document text
    • http://klpa.net/userData/board/file/36604291834.pdfIn PDF document text
    • http://xdata.pl/app/webroot/img/ckf/files/ladojig.pdfIn PDF document text
    • http://chekeeh.ir/basefile/chekeehir/files/sipikenavelu.pdfIn PDF document text
    • http://entryexpress.online/chapter_images/files/zibafatinusejujovu.pdfIn PDF document text
    • http://co-mit.com/uploads/files/12177948056.pdfIn PDF document text
    • http://www.acefence.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614bdc1fc4d5b---54198521833.pdfIn PDF document text
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/16140eb28d2c9c---37820049455.pdfIn PDF document text
    • http://beauty214.com/uploads/files/202109230528367587.pdfIn PDF document text
    • http://madinagirls.com/easydo%20v2.00/files/uploads/59480891079.pdfIn PDF document text
    • http://jonme.net/ckupload/files/xozazakex.pdfIn PDF document text
    • https://glasschneider.koeln/wp-content/plugins/super-forms/uploads/php/files/t19g5s3pip738b6c9fpdrki28e/wutululomerivejebe.pdfIn PDF document text
    • https://guineaservicesproviders.com/gsp/files/vonadijitakufiwamejo.pdfIn PDF document text
    • https://anjingliar.com/contents/files/40329460306.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_off0000ccca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCCA 17788 bytes
SHA-256: 75ee0cc6a04195647b68b01f94821b7523f8081df45f9140f8b58335312bf1bb
font_01_sfnt_off0000faff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAFF 10392 bytes
SHA-256: 77f27ae4f4a119aff666fe98177a7217e3a5f61b2c1ca28bef4afc219a787cbc
font_02_sfnt_off00011287.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11287 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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