Malicious PDF — malware analysis report

Static analysis result for SHA-256 42c8c1b67defb02c…

MALICIOUS

PDF

92.5 KB Created: 2021-07-08 21:30:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 59d69b2d0e5e532edb528ac9361a0d8e SHA-1: b5a29f1545d730c2e80267f93b88f795db81ed09 SHA-256: 42c8c1b67defb02c387f6eaec53620c512e6a86b925d697d41a65c81f2a46a12
96 Risk Score

Malware Insights

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

The PDF sample was identified as malicious by an ML classifier and exhibits characteristics of a link farm. It contains numerous links pointing to compromised CMS upload directories and disposable hosting domains, suggesting an attempt to redirect users to malicious content. No scripts were extracted, and the document body was heavily obfuscated, limiting further analysis of its specific lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 5

  • 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://adlinefor.com/home/webagen/public_html/korn/data/file/mizetasomebu.pdf
    • https://www.carlosfunes.es/wp-content/plugins/formcraft/file-upload/server/content/files/160a5cb2eb5c9c---86300606294.pdf
    • https://www.dekleinewerf.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160ac4b1828c6a---viliz.pdf
    • https://encouragingmath.com/wp-content/plugins/super-forms/uploads/php/files/329895cd12554d65afd40d9b569cd814/fotawebokirovono.pdf
    • http://komputerzagrosze.pl/userfiles/file/dejejos.pdf
    • http://chingyi.tw/userfiles/files/3727700809.pdf
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607516db8ff2a---rovunurezexij.pdf
    • https://godparents4tz.org/home/god/public_html/ckfinder/userfiles/files/tupixurukubenebanuko.pdf
    • https://ghnservizi.com/file/motowibegufi.pdf
    • https://bandai-k.com/userfiles/file/jogupa.pdf
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/160769740f41c7---fufemadesum.pdf
    • https://bettenbaehren.de/wp-content/plugins/formcraft/file-upload/server/content/files/1608bcac2abf1e---93926116065.pdf
    • http://t-p-fortune.com/userfiles/file/kikutegogesabifewi.pdf
    • http://www.agrosystem.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160b6ebbe5dc42---xiridiramovuvu.pdf
    • http://antwerp-rentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b298668238---1283282099.pdf
    • http://daegyung.kr/userfiles/file/20210707024744.pdf
    • http://boulderdivorcelaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/160db295007e6c---17307009375.pdf
    • http://pritchardreunion.com/clients/81409/File/mexarixizini.pdf
    • https://mamproducciones.es/wp-content/plugins/formcraft/file-upload/server/content/files/16078d04a01557---wiwasamafufatito.pdf
    • https://parisautotravel.com/wp-content/plugins/super-forms/uploads/php/files/nv6ptikvvsic3v0iokotj83611/silelab.pdf
    • http://prestopc.it/upload/file/jolijebepunekuvegesoz.pdf
    • https://www.fmworks.com.tr/wp-content/plugins/super-forms/uploads/php/files/0njgavpmg077913tpmgccdcc9m/vibubodipezu.pdf
    • http://accurateverdicts.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090257f7d613---18210695015.pdf
    • https://ocbond.org/userfiles/files/75605271366.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=how+to+get+pack+punch+cold+war
    • 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_off0001069c.bin
b2a0a6b4a10086c7c80a5b41f5225c64a0b9678e6333368db77fb54d0da31947
pdf-font-stream PDF embedded font (sfnt) at offset 0x1069C 10804 bytes
font_01_sfnt_off00011f4a.bin
855c848d7fbc9df3976bfdbd7083bd54c36e2406d428f8709e7f469e349acd48
pdf-font-stream PDF embedded font (sfnt) at offset 0x11F4A 17300 bytes
font_02_sfnt_off00014cb8.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x14CB8 16792 bytes