Malicious PDF — malware analysis report

Static analysis result for SHA-256 538b11c9efbe3323…

MALICIOUS

PDF

87.9 KB Created: 2021-08-10 00:02:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: f7f2ba4803c1a7e3ac0ba7eea5e81bd2 SHA-1: 2d1555f8ba700e859d71165b2bc79cfb7ee0e346 SHA-256: 538b11c9efbe33237f90ea1c2948f484e0271c3699bd4612bfe28ea4ad8dd188
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many hosted on compromised WordPress sites or disposable domains, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery. While no scripts were explicitly extracted, the PDF structure and heuristic firings point towards a malicious document used as a lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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 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://huntic.ru/uplcv?utm_term=what+are+nec+codes
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160c145322375f---60866881022.pdf
    • http://royalwedding.jp/images/blog//file/rulikuwovifiwufuz.pdf
    • http://vakantie-noordlimburg.nl/ckfinder/userfiles/files/61158109019.pdf
    • https://ambulatorioveterinariosismondi.eu/file/90628588508.pdf
    • http://dade666.com/userfiles/202107file/2021070419434670554.pdf
    • http://creptiles.dk/userfiles/file/72083726960.pdf
    • https://tigapilar.com/upload/files/25516493223.pdf
    • http://mountmedpharmacy.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/16071c550baef8---25270169607.pdf
    • http://www.myhhsi.com/wp-content/plugins/super-forms/uploads/php/files/be1dfd5f74f89c2c301c5f7496518c00/wunosujo.pdf
    • https://snabavto.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bb019086c9e---xiguzinasexuvozuwo.pdf
    • https://parkettworld.com/upload/files/24352301125.pdf
    • https://bhsbeacon.com/FCKeditor/file/xevov.pdf
    • http://mirembeestate.co.ug/wp-content/plugins/formcraft/file-upload/server/content/files/16106c30aeb014---24351195450.pdf
    • http://sieckultury.pl/wp-content/plugins/super-forms/uploads/php/files/b1f588a2945b6934bbf4b3b4b1fed0d4/39633675093.pdf
    • https://home18.ru/wp-content/plugins/super-forms/uploads/php/files/7ba74847c01aaf5bba7d789f4da02686/wodisemosajafapinekexawa.pdf
    • http://ranaghatpchsschool.org/userfiles/file/bivedajigosuxirepufoja.pdf
    • https://www.temsilcifirsatlari.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074298a94ca1---10383095815.pdf
    • https://harpethvalleyhealth.com/wp-content/plugins/super-forms/uploads/php/files/0976ba30b59091c2afca52f95c31509c/dapudaxiweruvupafesi.pdf
    • https://ruta.hu/ckfinder/userfiles/files/doresasabipuki.pdf
    • http://kwik-it.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160e2e7ff254da---26545935355.pdf
    • http://victorylimo1.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f22755a0a64---vifujejozozididevatufubo.pdf
    • https://khambenhxahoi115.com/images/files/52041051355.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_off0000f394.bin
bfaa9e7ba46d2fd7cf9ffde2df8871660dc8141226a8cc94d8ee194f0433aa9f
pdf-font-stream PDF embedded font (sfnt) at offset 0xF394 10320 bytes
font_01_sfnt_off00010add.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10ADD 16792 bytes
font_02_sfnt_off000122ef.bin
65b22ee7facfed034000923880821e55c0185e016eed5df4551901b09c6eed1e
pdf-font-stream PDF embedded font (sfnt) at offset 0x122EF 17972 bytes