Malicious PDF — malware analysis report

Static analysis result for SHA-256 21553e42503e63ef…

MALICIOUS

PDF

81.7 KB Created: 2021-09-17 19:53:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 199a3c4e2f8e142426e9c01518941a16 SHA-1: 4b0a0f6bbda2e971909b10280138d9d90a2cca6c SHA-256: 21553e42503e63effd6f4e98e3399647eadfd8ed6a080e1fd0c803d004f8e6ba
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed for malicious redirection. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. No scripts were extracted, but the structure and URL patterns are indicative of a common malicious PDF distribution method.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • 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.
  • 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://irlanc.ru/uplcv?utm_term=download+videos+from+android+phone+to+computer PDF link annotation
    • http://ukrfirework.com/images/file/dumopomi.pdfIn PDF document text
    • https://calienglish.com/ckfinder/images_store/files/rikakupawolopuzox.pdfIn PDF document text
    • https://lerong.vn/wp-content/plugins/super-forms/uploads/php/files/363e1385760a729acd1485b9a098fb6d/wijijuxusunululur.pdfIn PDF document text
    • http://winfielddeli.com/ckfinder/userfiles/files/73934630582.pdfIn PDF document text
    • https://alirezamirmohammadi.com/images/upload/files/98299397971.pdfIn PDF document text
    • https://frisch.ro/files/file/sakugofiwazuki.pdfIn PDF document text
    • http://foto-preiss.at/upload_files/files/52865957999.pdfIn PDF document text
    • http://defhjdr.friend-match.com/upload/files/13399924280.pdfIn PDF document text
    • https://aymsoft.us/aym_image/files/xubonulesu.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/161313d30697d0---fosanonone.pdfIn PDF document text
    • http://atreve.eu/ubezpiecz/obrazy/file/57443814901.pdfIn PDF document text
    • https://natyabio.com/uploadfiles/64834528650.pdfIn PDF document text
    • http://print-printonline.com/ckfinder/userfiles/files/mijuwilopipogevagavajaz.pdfIn PDF document text
    • https://marupyara.com/fotos/userfiles/file/35003219554.pdfIn PDF document text
    • http://farashimirooz.com/files/56499003343.pdfIn PDF document text
    • https://swaarm.de/app/webroot/upload/files/boxuloma.pdfIn PDF document text
    • https://gservicepz.com/wp-content/plugins/super-forms/uploads/php/files/f34e6cfe021e7d11fcdec7ae451c4d1e/88365878830.pdfIn PDF document text
    • http://laptopplus.be/app/webroot/files/userfiles/files/59354968637.pdfIn PDF document text
    • http://np-laser.com/upload_fck/file/2021-9-5/20210905000152253608.pdfIn PDF document text
    • http://yuhongzg.com/d/files/29877565189.pdfIn PDF document text
    • https://www.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1613b52bf9101c---xonofidixezojoxakiw.pdfIn PDF document text
    • https://samsungklimamodelleri.com/upload/ckfinder/files/4613366124.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_off0000d86f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD86F 17744 bytes
SHA-256: 416da6832cb17dd2f6fb394104061d0af2e166374c33adc1cd61c61eafbd23ad
font_01_sfnt_off000106da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106DA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011ef1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EF1 11136 bytes
SHA-256: 654c9ad70a100616eade9c1504c8058e4fd3f76180071b87eaade46ff7f6079d