Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8b77f07d581dc67…

MALICIOUS

PDF

82.7 KB Created: 2021-09-08 00:04:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 4e392dbd952fb6461ccf7bd03452c7f5 SHA-1: 76fff0ddceb3cd156dd595ca43b51cfa2ca749c4 SHA-256: b8b77f07d581dc67a4af5bd1dc4b2d86ce3c5199224f50eebf880de743720fa4
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript, which is a common technique for delivering malicious payloads or redirecting users to phishing sites. Several heuristics indicate the PDF is part of a link farm hosted on compromised or disposable domains, suggesting a phishing or malware distribution campaign. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://synerhu.ru/uplcv?utm_term=how+do+you+redact+information+from+a+pdf+document PDF link annotation
    • http://thietbimaugiao.vn/Images_upload/files/86096676696.pdfIn PDF document text
    • http://fotossc.pl/_files/file/30485687388.pdfIn PDF document text
    • http://jinanxintiandi.com/userfiles/files/50382270924.pdfIn PDF document text
    • https://rjiminfra.com/wp-content/plugins/super-forms/uploads/php/files/a2e1ddcb3ee6a8906159473e17dc80bb/zirolo.pdfIn PDF document text
    • https://pensiunea-escape.ro/ckfinder/userfiles/files/15986605839.pdfIn PDF document text
    • https://k-newsletter.com/ckupload/files/49498457698.pdfIn PDF document text
    • http://starlightcelebrates.org/clients/4/43/43e9139217482d7666ce300faf566241/File/43267741895.pdfIn PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1607e38fa4d26a---dunilujop.pdfIn PDF document text
    • https://memorybg.net/app/templates/js/ckfinder/userfiles/files/gevigeriwuwuxorakixopuz.pdfIn PDF document text
    • http://yalcinsezer.com/upload/ckfinder/files/dositog.pdfIn PDF document text
    • https://motodubai.com/uploaded_images/files/50769492979.pdfIn PDF document text
    • http://subventionsbetrug.de/wp-content/plugins/super-forms/uploads/php/files/t6in97lplk3mhijtju5mntt2am/671061092.pdfIn PDF document text
    • https://efnnma.org/files/file/xuragujoxo.pdfIn PDF document text
    • http://schodylux.pl/userfiles/file/turikukalixide.pdfIn PDF document text
    • http://szyoujin.com/UploadFile/file/20210817224347551.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160a0321d27232---berijixiwarapovajinu.pdfIn PDF document text
    • https://akapacha.com/userfiles/file/80111195152.pdfIn PDF document text
    • http://newmob.it/userfiles/files/37881858105.pdfIn PDF document text
    • http://compie.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1611fd3246d270---65554760016.pdfIn PDF document text
    • http://dmn.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1606f36b77c003---30727186919.pdfIn PDF document text
    • http://lindseyderence.com/userfiles/files/31880278043.pdfIn PDF document text
    • http://oprandi.it/userfiles/files/57511410122.pdfIn PDF document text
    • http://nhadatv.com/webroot/img/files/lawekebimofusubabikejo.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_off0000dd07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD07 18156 bytes
SHA-256: 31cfe927a5df7663f8ff0eec8922c1081816ba1576674c6b6f95ed578b916950
font_01_sfnt_off00010bad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10BAD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000123c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123C4 10860 bytes
SHA-256: 1ef5e5017117fc8d5f61f121dac735bd8f4e78ed8bcf2d81262f8d28e4c121e6

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