Malicious PDF — malware analysis report

Static analysis result for SHA-256 51b9c4ee18cc5c4b…

MALICIOUS

PDF

77.6 KB Created: 2021-07-23 17:38:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 565f99e55fa7abbbebfaa9aea50abc79 SHA-1: 7dd9bb8ba92052b318d872911309c9ba43dd1492 SHA-256: 51b9c4ee18cc5c4b61a67358e05eacef90d36e67a5fe3c4d73343ce374fc3120
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a high number of embedded links, many pointing to compromised CMS uploads and disposable hosting, indicating a link farm designed to redirect users to malicious content. The ClamAV detection and ML classifier strongly suggest this PDF is malicious, likely serving as a phishing lure or a distribution point for further malware. No scripts were extracted, but the numerous URLs are the primary indicators of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9943

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://searchkar.com/ci/userfiles/files/tazabisoxidemaloxoxubowi.pdf
    • https://lamaisonducoeur.ca/upload/editor/file/jodevajotakiguxozuji.pdf
    • https://nacionalequipamentos.com/ckeditor/uploads/files/20931190652.pdf
    • https://butterfly-propertymanagement.com/userfiles/file/9822697248.pdf
    • http://bmsorganica.com/userfiles/file/12480037086.pdf
    • https://ewt.cz/res/file/pikewerugomenidotim.pdf
    • http://goraku-sangyo.com/userfiles/file/sapuxunupowatepomefori.pdf
    • https://samarpanbharat.org/trila/userfiles/file/8555240352.pdf
    • http://aprendanow.com/wp-content/plugins/super-forms/uploads/php/files/7462ebd512a8d8bfad23b8e806fd1626/6526823156.pdf
    • http://go-trec.com/wp-content/plugins/super-forms/uploads/php/files/aq9q1ckssmmldctor13pqigmni/xevikovozopalobariline.pdf
    • https://funkydrop.shop/wp-content/plugins/super-forms/uploads/php/files/7cd95b8a97e6918772866d2d10197f72/lusisufukavodiwovimod.pdf
    • http://przedszkolenisko.pl/userfiles/file/14056037535.pdf
    • http://dreamcatcherltd.com/userfiles/file/bujuti.pdf
    • https://www.hed-endo.hr/wp-content/plugins/formcraft/file-upload/server/content/files/160ab72d2401a0---50923392390.pdf
    • https://sieuthimayphat.com/ckfinder/userfiles/files/lixoxumaxoluretererotex.pdf
    • http://bajcsidavidfoto.com/_user/file/209856658.pdf
    • http://ebbers-schilderwerken.nl/uploads/files/43955553734.pdf
    • http://villabrown.it/userfiles/files/86431977035.pdf
    • http://studiomistretta.com/userfiles/files/5697790504.pdf
    • https://skazkavdom.com/wp-content/plugins/super-forms/uploads/php/files/7c175531154c389d9809ee33504a7ea2/ponobefu.pdf
    • http://ambulatorioveterinariopisillibertozzi.eu/userfiles/files/zivizemefaminiboxudawof.pdf
    • http://timeyear-v.com/userfiles/file/wifuzadajonijepegejok.pdf
    • http://www.fattyweng.com.sg/wp-content/plugins/formcraft/file-upload/server/content/files/160aea85f01966---zuvarimezosikekizonubi.pdf
    • http://jcpingie.be/public/files/buluxuxum.pdf
    • https://moscowfashion.net/content/xuploadimages/file/13414749805.pdf
    • http://cl-pub.com/files/files/99414399923.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=ejercicios+de+factorizar+de+la+forma+x2%2Bbx%2Bc
    • 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_off0000ca10.bin
a73c0104678521102ab9bb9142aa39e16892e935bc557dbaf14fd7d8747b9469
pdf-font-stream PDF embedded font (sfnt) at offset 0xCA10 17256 bytes
font_01_sfnt_off0000f604.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF604 16792 bytes
font_02_sfnt_off00010e1b.bin
0c11ba421a1fe92d9dff89d688a16c52f85ecad88e6d164e0f30015be356f8b6
pdf-font-stream PDF embedded font (sfnt) at offset 0x10E1B 11068 bytes