Malicious PDF — malware analysis report

Static analysis result for SHA-256 5ca4953878e1b3a9…

MALICIOUS

PDF

74.9 KB Created: 2021-09-06 00:06:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: de845b360b53c815b463ffed40140997 SHA-1: 1c72d9a4328609dd8c8b6867c44af0594c6e3b11 SHA-256: 5ca4953878e1b3a9aa3dd6e8be8d97c1869ab37a086bc98e72bdb2096068375e
156 Risk Score

Malware Insights

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

The PDF document contains numerous embedded URLs, many of which point to compromised WordPress sites and disposable domains, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. The document body is heavily obfuscated and unreadable, providing no direct content clues, but the heuristic firings are sufficient to infer a malicious link-farming pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://maybaobidinhdinh.com/upload/files/jigozibivo.pdf In PDF document text
    • https://alamansyria.com/userfiles/file/63322745328.pdfIn PDF document text
    • http://smalternatywa.pl/media/upload/files/cea111b89154bd6b650be1a443290408.pdfIn PDF document text
    • http://leaguengn.com/userfiles/file///javotobe.pdfIn PDF document text
    • https://laser-arena.ch/wp-content/plugins/formcraft/file-upload/server/content/files/1608abe17552ae---ludubepamax.pdfIn PDF document text
    • https://intelean.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c97d8121a0d---28794093236.pdfIn PDF document text
    • https://malimbe.africa/wp-content/plugins/super-forms/uploads/php/files/9c78dbe694e8f439809bbc2c4f3c8db4/tavomekuvureset.pdfIn PDF document text
    • http://singer-island-condos.com/userfiles/files/jenub.pdfIn PDF document text
    • https://www.rogierstoel.nl/wp-content/plugins/super-forms/uploads/php/files/hpt9312fvho7q2d7h2pghpbqlu/bunapuwopalozorisi.pdfIn PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160b8b2ff6e4e4---zikujefijuxopijo.pdfIn PDF document text
    • http://hk-sai.com/ckfinder/userfiles/files/83621792555.pdfIn PDF document text
    • http://eldorautomaticgates.com/UserFiles/file/vuguvetitaf.pdfIn PDF document text
    • https://podgoricki-klub.me/userfiles/file/46341565720.pdfIn PDF document text
    • https://adamant54.ru/userfiles/files/zowiworebi.pdfIn PDF document text
    • http://intestinalfortitude.org/clients/0/0c/0cf504f131cb0201443a7bd449519f4a/File/rikojofekewepobijipev.pdfIn PDF document text
    • http://eshop-kocicinadeje.cz/files/file/43559634550.pdfIn PDF document text
    • http://grapes4u.ca/sites/all/sites/grapes4u.ca/files/40082370313.pdfIn PDF document text
    • http://f-okinawa.com/img/tmp/files/10904945897.pdfIn PDF document text
    • https://www.cosanuesa.com/componentes/editor/ckfinder/userfiles/files/repive.pdfIn PDF document text
    • http://erh-hu.com/userfiles/file/96860278779.pdfIn PDF document text
    • http://mega.kz/media/upload/files/94925175248.pdfIn PDF document text
    • http://www.contectrade.hu/fckfiles/file/lonadepinuwexaweravaza.pdfIn PDF document text
    • http://aiswaryamatrimonials.com/fck_uploads/file/wufubuwufurudi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=tuberculosis+intestinal+pdf+2017PDF 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_off0000c00f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC00F 17040 bytes
SHA-256: d77a750ef13626995c8fc330610ffb23555531d5d81d0808b6c1117f1026c17d
font_01_sfnt_off0000ec4b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC4B 11160 bytes
SHA-256: 1bcc1bc14b850871ef8e1d45cc5902c88accc07d6719320ce3e6c20e3f84b636
font_02_sfnt_off00010665.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10665 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1