Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1f4cd8de756afd4…

MALICIOUS

PDF

92.5 KB Created: 2021-09-21 16:24:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 05767edf14dd047a091383a217ed0335 SHA-1: cbd221f0e30e11462af7c60d997fac1de154c694 SHA-256: b1f4cd8de756afd44d688ff89ce4619218613f4c680ea565a8821b007df73886
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 disposable hosting or compromised CMS upload directories, indicative of a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. The presence of multiple external URIs and link farm heuristics points towards an attempt to lure users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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 https://pistant.ru/uplcv?utm_term=nexus+10+stock+rom
    • http://healhumanity.foundation/userfiles/file/bikozujujali.pdf
    • http://happy-land.hu/editor_up/56237281667.pdf
    • https://sunarchegypt.com/userfiles/file/gitok.pdf
    • http://wxbeimei.cn/upload/ckimg/files/202109210249109768.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/161485d47d73d9---86897425329.pdf
    • https://webmakler.org/userfiles/file/47523331992.pdf
    • http://geasit.it/userfiles/files/rerebazisunabeworumipid.pdf
    • https://www.icicle-mountaineering.ltd.uk/ckfinder/userfiles/files/21096652895.pdf
    • https://anitt.in/ckfinder/userfiles/files/pemuvesurigexefojob.pdf
    • http://vsrru.ru/userfiles/file/83332026048.pdf
    • http://venkateshservices.com/uploads/lenur.pdf
    • http://zhongguohuachun.com/d/files/sozapezilegiworofutofa.pdf
    • http://www.commandinglife.com/wp-content/plugins/formcraft/file-upload/server/content/files/161451cae14d0f---kedadixonanaposisatogine.pdf
    • http://hongsung114.com/files/fckeditor/file/57018084567.pdf
    • https://techinnsrl.com/writable/public/userfiles/file/38635570957.pdf
    • http://mxag.com/upload/browse/file/76856211019.pdf
    • https://archielectronics.com/userfiles/files/51485407673.pdf
    • http://sergeisurzhin.ru/ckfinder/userfiles/files/maselipeduliparusevamafax.pdf
    • https://insights3.com/wp-content/plugins/super-forms/uploads/php/files/9068a78fdc223d36df253e199c8149e0/nefokejisenirawe.pdf
    • 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_off0000ffd8.bin
fa77273321327154de93c1f1ab66b79b4743b323d0f8656d16598609d8201578		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFFD8 10432 bytes
font_01_sfnt_off000117b0.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x117B0 16792 bytes
font_02_sfnt_off00012fc2.bin
be29b793f9c6384ac790a8c3142c16f1d3e6a800c0033c1df20ace68ed631fdb		 pdf-font-stream PDF embedded font (sfnt) at offset 0x12FC2 19948 bytes

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