Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c4f9c3cf540cb47…

MALICIOUS

PDF

98.6 KB Created: 2021-08-23 09:26:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 5f6d3a93813a9d88908d95e1e7eda051 SHA-1: 31facb3f81a1f59580113ffd67559953cf092145 SHA-256: 5c4f9c3cf540cb47b5d1f01592df249fb2ce8bc75150cc469df3d6bb3e6a1a4d
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple links pointing to compromised WordPress sites, acting as a link farm to host malicious files. The ClamAV detection and ML classifier strongly indicate malicious intent, likely to deliver a secondary payload. The presence of embedded URLs and the nature of the link farms suggest an attempt to disguise the distribution of malware, potentially through spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://www.rlktechniek.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16077ccb317527---34602751353.pdf
    • http://sntaviator.ru/ckfinder/userfiles/files/28737018352.pdf
    • https://drivingschoolofnorthtexas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16114676ee34c2---siteraxuzugokokasasimad.pdf
    • http://sjar-tech.com/uploadfile/file///2021070201174184.pdf
    • http://www.kocay.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160d4170512d26---zufejodex.pdf
    • http://www.findvoters.com/userfiles/file/14676323089.pdf
    • https://spazmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073b74af3393---38676817069.pdf
    • https://tylbm.com/Upload/ckeditor/files/xaluz.pdf
    • https://stellabakingcompany.com/wp-content/plugins/formcraft/file-upload/server/content/files/16080129b354e2---75104071542.pdf
    • http://hattrick-sports.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b27fcc86e29---talonolatowakikidax.pdf
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/160abb78851c43---sowemikiduxaka.pdf
    • https://ost-fogging.com/upload/files/4357895912.pdf
    • http://www.cascinasorigherio.it/wp-content/plugins/formcraft/file-upload/server/content/files/160739c08cdaf2---3234163576.pdf
    • http://iehyun.com/editorupload/file/52710167621.pdf
    • https://netwindowvn.com/uploads/userfiles/file/20507636804.pdf
    • https://tocgia247.com/wp-content/plugins/super-forms/uploads/php/files/dpbf0lujpqrvsop8omjc3tt1k4/45390467586.pdf
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607caf1ec4818---xukalep.pdf
    • https://www.elshandmadedesign.nl/ckfinder/userfiles/files/58976026124.pdf
    • http://jyjwqj.com/uploadfile/file///2021062819114212.pdf
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610aff32ef794---11340351736.pdf
    • http://fotomil.pl/ckfinder/userfiles/files/ninatisojewalazaxofita.pdf
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/40073298648.pdf
    • https://www.frankcapassoandsons.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bda54f7fde4---delositotapojepunug.pdf
    • https://media-get.ru/userfiles/files/zagoregisowipujepemisesem.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=heaviest+weighted+pull+up
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00011b08.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11B08 16792 bytes
font_01_sfnt_off0001331f.bin
bfc7fde1447ca9fe05c8c0b47a837eb9629741fabfc3da5b0b86b1af88c6bdf2
pdf-font-stream PDF embedded font (sfnt) at offset 0x1331F 10592 bytes
font_02_sfnt_off00014b3c.bin
c2b344aad45c46f30e1bde5f24cb4fcb27b2395d10fb417e2170333477b224e8
pdf-font-stream PDF embedded font (sfnt) at offset 0x14B3C 19264 bytes