Malicious PDF — malware analysis report

Static analysis result for SHA-256 316e98cae3388d7f…

MALICIOUS

PDF

71.3 KB Created: 2021-10-03 11:14:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 5df1205f70e88a58d9b207a2d4356982 SHA-1: 8ef797724603dcd20c82b6f4c19e82c9ee8ad0ad SHA-256: 316e98cae3388d7fe0bef86fd4cb0b6aa83cc0d55632e407f30d3a020b18199f
96 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to compromised websites or disposable hosting. The ML classifier strongly indicated maliciousness, and the structure suggests a link farm designed to redirect users to potentially harmful content. No scripts were extracted, limiting the analysis of direct execution vectors.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://huntic.ru/uplcv?utm_term=save+website+as+pdf+firefox PDF link annotation
    • http://handgun.ee/media/file/rered.pdfIn PDF document text
    • https://esvigo.com/upload/files/48502584299.pdfIn PDF document text
    • http://coolscape.info/images/files/wupowikaperez.pdfIn PDF document text
    • http://thegioimercedes.com/upload/files/ribupubiluranusaladoxar.pdfIn PDF document text
    • http://rovitek.com/userfiles/file/12596983965.pdfIn PDF document text
    • https://nazrabilisim.com/calisma2/files/uploads/zuvebaduwixo.pdfIn PDF document text
    • https://astoriareiki.com/wp-content/plugins/super-forms/uploads/php/files/3317047d66c49b3bb58c5c719f2634c5/nenikupilulasuzafozem.pdfIn PDF document text
    • https://www.privathospitaletkollund.com/ckfinder/userfiles/files/toriz.pdfIn PDF document text
    • https://tomorrowhubs.com/upload/users/files/58269054513.pdfIn PDF document text
    • http://kleiberit.ru/files/file/zezuv.pdfIn PDF document text
    • https://millersexpress.com/userfiles/file/12604937204.pdfIn PDF document text
    • https://www.elementstraining.co.uk/wp-content/plugins/super-forms/uploads/php/files/nj4je925ekb0pksmll7qlsg2km/kuvoxoso.pdfIn PDF document text
    • https://monamifrance.com/FileData/ckfinder/files/20210930_5B2880C080DD0E3F.pdfIn PDF document text
    • http://gabortech.com/admin/file/97607916637.pdfIn PDF document text
    • https://thuaphatlaihanoi.net/uploads/files/92692659065.pdfIn PDF document text
    • http://www.cascinasorigherio.it/wp-content/plugins/formcraft/file-upload/server/content/files/1612fde385abee---sekuxepusibob.pdfIn PDF document text
    • http://decorstore.eu/upload/file/79340557926.pdfIn PDF document text
    • https://monyetmesum.com/contents/files/27994473615.pdfIn PDF document text
    • http://fine-cottage.ru/userfiles/files/40447677630.pdfIn PDF document text
    • https://nayyaralidada.net/alpha/ckfinder/userfiles/files/69217406298.pdfIn PDF document text
    • https://robert-zauer.cz/userfiles/file/11637821796.pdfIn PDF document text
    • http://nanumed.ro/uploads/files/98381172218.pdfIn PDF document text
    • http://getvisa.ru/images/File/butej.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_off0000b3f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB3F1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cc08.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC08 10808 bytes
SHA-256: e71c7d345df5539a6560dbb5c99883a4f9f4eb12a67617eff345ce81803240c3
font_02_sfnt_off0000e4ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4EA 16792 bytes
SHA-256: 9b55a942c30a391c64afa891669796b2dcefb4195a2561994e19e3ee9ca8c47c