Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b85079b4a3231ae…

MALICIOUS

PDF

74.3 KB Created: 2021-03-08 02:14:16 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 67166e35fc954b3f0418ff62bacdf27e SHA-1: ec32aab79336e53d47eafed94fcc2d8d717989d7 SHA-256: 5b85079b4a3231ae24163bd5f81d5907dfa3b82f949a541405282da526ed7ed1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The document body, though heavily obfuscated, suggests a lure related to study guide answers. The presence of numerous external links, including one pointing to `midufefew.ru`, strongly suggests a phishing or redirection attempt. The `PDF_SEO_LINK_FARM` heuristic further supports the idea that the PDF is designed to host a large number of external links, likely for malicious purposes.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://midufefew.ru/wix?keyword=the+official+sat+study+guide+second+edition+answers
    • http://nudukuju.22web.org/string_format_2_decimal_places_c.pdf
    • https://zodazapel.weebly.com/uploads/1/3/4/5/134511258/6a4e2bd4a9.pdf
    • https://valexipeval.weebly.com/uploads/1/3/0/7/130775413/kedowifu.pdf
    • http://mevakimuvu.mypressonline.com/75098353771.pdf
    • http://gopubewigofopa.iblogger.org/37718925094.pdf
    • https://rijevolokawuja.weebly.com/uploads/1/3/4/6/134661742/0773f77.pdf
    • http://tigafik.mygamesonline.org/english_speaking_eye_clinic_near_me.pdf
    • https://zamomojufowa.weebly.com/uploads/1/3/4/6/134613680/zodefedisiteso.pdf
    • https://totovipuvo.weebly.com/uploads/1/3/2/7/132740708/luwemukoti-vozuzagetuk-bavizefat-lapolitemukiw.pdf
    • http://tewatag.medianewsonline.com/veniwubonetusepurevotodev.pdf
    • http://narelarijejale.iblogger.org/killing_joke_pandemonium_shirt.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/bulikowexunepov/ziroladikerakosiruf.pdf
    • http://katuribadelu.rf.gd/86670771932.pdf
    • https://s3.amazonaws.com/legenapi/government_petition_template.pdf
    • http://validexa.epizy.com/86599179728.pdf
    • https://s3.amazonaws.com/gazijewevan/nirijizixoxukotudi.pdf
    • https://s3.amazonaws.com/dewutexorob/axl_full_movie_480p.pdf
    • http://zunedolu.rf.gd/39751481995.pdf
    • http://danidarexixuw.epizy.com/70019362286.pdf
    • http://bigapenegig.atwebpages.com/63118014793.pdf
    • https://s3.amazonaws.com/gixawetopoli/reloading_bench_for_sale_canada.pdf
    • https://s3.amazonaws.com/bejokazemur/32025171990.pdf
    • http://misanedajog.myartsonline.com/rufidunibunofununuz.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://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e686.bin
040664620dcfc2b59ad5142ed218943e36fa3c8218f96d4a8fbdbe5c9030db18		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE686 5424 bytes
font_01_sfnt_off0000f910.bin
4a523efb1562691b17d9fd56be54826aeb9c4d682053bb718220232531cd9ab0		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF910 10076 bytes

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