Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4554f83183b9bb8…

MALICIOUS

PDF

82.6 KB Created: 2021-07-05 01:42:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 135a8bcb1549f43e0855a7cdca2373ab SHA-1: cc2d6d602946aabec34d7986ad0ddcabfb231cc4 SHA-256: b4554f83183b9bb82b11b041e9c8db87c78df82b98155abefca3f477184516db
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which are hosted on compromised WordPress sites or disposable hosting, indicating a link farm designed for malicious redirection. The ClamAV detection and ML classifier strongly suggest a phishing or trojan payload delivery. The document body is heavily obfuscated and unreadable, providing no direct user-facing content, but the heuristic firings confirm the malicious intent of the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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://chcial.ru/uplcv?utm_term=hex+to+octal+converter+with+steps
    • http://www.inhd.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608331ebf2a1e---gesimimusenotoz.pdf
    • http://nhadatv.com/webroot/img/files/manilipetanonasuf.pdf
    • https://tungqibiotech.com/upfiles/editor/files/62152517969.pdf
    • http://4seasonstours.in/userfiles/file/pumoziz.pdf
    • https://swift-tw.com/lcc/upload/files/43075609864.pdf
    • https://stakeoutllc.com/wp-content/plugins/super-forms/uploads/php/files/1a6bbbaeecaa78f58740571f7e3ffdaa/dobetan.pdf
    • http://hyderabadibiryanicorner.com/admin/images/file/tonab.pdf
    • https://readxyz.com/wp-content/plugins/super-forms/uploads/php/files/92e7ade490115bb4af5beead465d3ab1/tokuwavuzorov.pdf
    • http://www.vandiestbrandstoffen.be/uploads/files/bireraro.pdf
    • https://evg-prague.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1606cc77acbed4---49731410497.pdf
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1609d341e7d34f---69294873124.pdf
    • http://www.uppld.org/wp-content/plugins/formcraft/file-upload/server/content/files/1606f228a1752b---29094827461.pdf
    • https://cms.blauraum.com/wp-content/plugins/super-forms/uploads/php/files/f5c457177a7a91127ab4bb27070bf4e0/sarerafofogefukitorezit.pdf
    • https://balajitutorial.com/admin/userfiles/file/pevezamonasopoxu.pdf
    • https://cottonweb.net/userfiles/file/navasojidofowo.pdf
    • https://118highschool.am/wp-content/plugins/super-forms/uploads/php/files/f8e2d29947e4527330f2da2d25b03416/46372790196.pdf
    • http://www.hydro-tg.pro/upload/file/vifimegovazavulivepe.pdf
    • http://www.magicapro.it/wp-content/plugins/formcraft/file-upload/server/content/files/160e1836e100e0---nigesujikat.pdf
    • https://functionalmovement.gr/wp-content/plugins/super-forms/uploads/php/files/97564562948435b2536967a21d5754d0/89251259116.pdf
    • http://kaies.cn/upfiles/file/94919675908.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608bda992f898---41197849021.pdf
    • https://christembassybarking.org/wp-content/plugins/super-forms/uploads/php/files/e5b1cc5c6d80b5d266ae5aad7ddd81cc/kemejufegesesosijefituto.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_off0000dc48.bin
8e5a7625c4b3ebcb75c494685a1533a3df1db0be76177d7c19217c6748229742
pdf-font-stream PDF embedded font (sfnt) at offset 0xDC48 10716 bytes
font_01_sfnt_off0000f4de.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF4DE 16792 bytes
font_02_sfnt_off00010cf0.bin
6196fc3cb92b3a8cb5384399e43153ac3006e2d3c2a07afbe6b1aa39c176998b
pdf-font-stream PDF embedded font (sfnt) at offset 0x10CF0 18212 bytes